50编程题及答案
【程序1】??? 題目：古典問(wèn)題：有一對(duì)兔子，從出生后第3個(gè)月起每個(gè)月都生一對(duì)兔子，小兔子長(zhǎng)到第三個(gè)月后每個(gè)月又生一對(duì)兔子，假如兔子都不死，問(wèn)每個(gè)月的兔子總數(shù)為多少？??? //這是一個(gè)菲波拉契數(shù)列問(wèn)題 public class lianxi01 { public static void main(String[] args) { System.out.println("第1個(gè)月的兔子對(duì)數(shù):??? 1"); System.out.println("第2個(gè)月的兔子對(duì)數(shù):??? 1"); int f1 = 1, f2 = 1, f, M=24; ???? for(int i=3; i<=M; i++) { ????? f = f2; ????? f2 = f1 + f2; ????? f1 = f; ????? System.out.println("第" + i +"個(gè)月的兔子對(duì)數(shù): "+f2); ???????? } } }
【程序2】??? 題目：判斷101-200之間有多少個(gè)素?cái)?shù)，并輸出所有素?cái)?shù)。 程序分析：判斷素?cái)?shù)的方法：用一個(gè)數(shù)分別去除2到sqrt(這個(gè)數(shù))，如果能被整除， 則表明此數(shù)不是素?cái)?shù)，反之是素?cái)?shù)。??? public class lianxi02 { public static void main(String[] args) { ??? int count = 0; ??? for(int i=101; i<200; i+=2) { ???? boolean b = false; ???? for(int j=2; j<=Math.sqrt(i); j++) ???? { ??????? if(i % j == 0) { b = false; break; } ???????? else?????????? ?{ b = true; } ???? } ??????? if(b == true) {count ++;System.out.println(i );} ????????????????????????????????? } ??? System.out.println( "素?cái)?shù)個(gè)數(shù)是: " + count); } }
【程序3】??? 題目：打印出所有的 "水仙花數(shù) "，所謂 "水仙花數(shù) "是指一個(gè)三位數(shù)，其各位數(shù)字立方和等于該數(shù)本身。例如：153是一個(gè) "水仙花數(shù) "，因?yàn)?/span>153=1的三次方＋5的三次方＋3的三次方。 public class lianxi03 { public static void main(String[] args) { ???? int b1, b2, b3; ???? for(int m=101; m<1000; m++) { ????? b3 = m / 100; ????? b2 = m % 100 / 10; ????? b1 = m %??? 10; ????? if((b3*b3*b3 + b2*b2*b2 + b1*b1*b1) == m) { ????? System.out.println(m+"是一個(gè)水仙花數(shù)"); } ???? } } }???
【程序4】??? 題目：將一個(gè)正整數(shù)分解質(zhì)因數(shù)。例如：輸入90,打印出90=2*3*3*5。??? 程序分析：對(duì)n進(jìn)行分解質(zhì)因數(shù)，應(yīng)先找到一個(gè)最小的質(zhì)數(shù)k，然后按下述步驟完成：??? (1)如果這個(gè)質(zhì)數(shù)恰等于n，則說(shuō)明分解質(zhì)因數(shù)的過(guò)程已經(jīng)結(jié)束，打印出即可。??? (2)如果n <> k，但n能被k整除，則應(yīng)打印出k的值，并用n除以k的商,作為新的正整數(shù)你n,重復(fù)執(zhí)行第一步。??? (3)如果n不能被k整除，則用k+1作為k的值,重復(fù)執(zhí)行第一步。?? import java.util.*; public???? class???? lianxi04{ ??? public static void main(String[] args) { ??????? Scanner s = new Scanner(System.in); ??????? System.out.print( "請(qǐng)鍵入一個(gè)正整數(shù):???? "); ??????? int??? n??? = s.nextInt(); ??????? int k=2; ??????? System.out.print(n + "=" ); ??????? while(k <= n) { ????????? if(k == n) {System.out.println(n);break;} ??????????? else if( n % k == 0) {System.out.print(k + "*");n = n / k; } ??????????????????? else??? k++; ?????????????????? } ???? } ??? } 【程序5】??? 題目：利用條件運(yùn)算符的嵌套來(lái)完成此題：學(xué)習(xí)成績(jī)> =90分的同學(xué)用A表示，60-89分之間的用B表示，60分以下的用C表示。??? import java.util.*; public class lianxi05 { public static void main(String[] args) { ???? int x; ???? char grade; ???? Scanner s = new Scanner(System.in); ???? System.out.print( "請(qǐng)輸入一個(gè)成績(jī): "); ???? x = s.nextInt();?? ???? grade = x >= 90 ? 'A' ?????????? : x >= 60 ? 'B' ?????????? :'C'; ??? System.out.println("等級(jí)為："+grade); ?? } } 【程序6】??? 題目：輸入兩個(gè)正整數(shù)m和n，求其最大公約數(shù)和最小公倍數(shù)。??? /**在循環(huán)中，只要除數(shù)不等于0，用較大數(shù)除以較小的數(shù)，將小的一個(gè)數(shù)作為下一輪循環(huán)的大數(shù)，取得的余數(shù)作為下一輪循環(huán)的較小的數(shù)，如此循環(huán)直到較小的數(shù)的值為0，返回較大的數(shù)，此數(shù)即為最大公約數(shù)，最小公倍數(shù)為兩數(shù)之積除以最大公約數(shù)。* / import java.util.*; public??? class???? lianxi06???? { public static void main(String[] args) { int???? a ,b,m; Scanner s = new Scanner(System.in); System.out.print( "鍵入一個(gè)整數(shù)： "); a = s.nextInt(); System.out.print( "再鍵入一個(gè)整數(shù)： "); b = s.nextInt(); ????? deff cd = new deff(); ????? m = cd.deff(a,b); ????? int n = a * b / m; ????? System.out.println("最大公約數(shù): " + m); ????? System.out.println("最小公倍數(shù): " + n); } } class deff{ public int deff(int x, int y) { ???? int t; ???? if(x < y) { ????? t = x; ????? x = y; ????? y = t; ???? }?? ???? while(y != 0) { ????? if(x == y) return x; ????? else { ?????? int k = x % y; ?????? x = y; ?????? y = k; ????? } ???? } ???? return x; } } 【程序7】??? 題目：輸入一行字符，分別統(tǒng)計(jì)出其中英文字母、空格、數(shù)字和其它字符的個(gè)數(shù)。???
package?WuYang;
import?java.util.*;
public?class?lianxi07 {
public?static?void?main(String[] args) {
??int?abcCount=0;//英文字母?jìng)€(gè)數(shù)
??int?spaceCount=0;//空格鍵個(gè)數(shù)
??int?numCount=0;//數(shù)字個(gè)數(shù)
??int?otherCount=0;//其他字符個(gè)數(shù)
??Scanner scan = new?Scanner(System.in);//掃描器接受控制臺(tái)的輸入信息
??System.out.println("輸入一組字符");
String str=scan.nextLine();//取出控制臺(tái)的一行信息,也就是你輸入的信息
?char[] ch = str.toCharArray();//把取道的字符串變成一個(gè)char數(shù)組
?????for(int?i=0;i<ch.length;i++){
??????if(Character.isLetter(ch[i])){
???????//判斷是否字母
???????abcCount++;
??????}
??????else?if(Character.isDigit(ch[i])){
???????//判斷是否數(shù)字
???????numCount++;
??????}
??????else?if(Character.isSpaceChar(ch[i])){
???????//判斷是否空格鍵
???????spaceCount++;
??????}
??????else{
???????//以上都不是則認(rèn)為是其他字符
???????otherCount++;
??????}
?????}
?????System.out.println("字母?jìng)€(gè)數(shù)："+abcCount);
?????System.out.println("數(shù)字個(gè)數(shù)："+numCount);
?????System.out.println("空格個(gè)數(shù)："+spaceCount);
?????System.out.println("其他字符個(gè)數(shù)："+otherCount);
?}
?
}
?
【程序8】??? 題目：求s=a+aa+aaa+aaaa+aa...a的值，其中a是一個(gè)數(shù)字。例如2+22+222+2222+22222(此時(shí)共有5個(gè)數(shù)相加)，幾個(gè)數(shù)相加有鍵盤控制。??? import java.util.*; public class lianxi08 { public static void main(String[] args) { ???? long a , b = 0, sum = 0; ???? Scanner s = new Scanner(System.in); ???? System.out.print("輸入數(shù)字a的值： "); ???? a = s.nextInt(); ???? System.out.print("輸入相加的項(xiàng)數(shù)："); ???? int n = s.nextInt(); ???? int i = 0; ???? while(i < n) { ????? b = b + a; ????? sum = sum + b; ????? a = a * 10; ????? ++ i; ???? } ????? System.out.println(sum); } } 【程序9】??? 題目：一個(gè)數(shù)如果恰好等于它的因子之和，這個(gè)數(shù)就稱為 "完數(shù) "。例如6=1＋2＋3.編程???? 找出1000以內(nèi)的所有完數(shù)。??? public class lianxi09 { public static void main(String[] args) { ???? System.out.println("1到1000的完數(shù)有： "); ???? for(int i=1; i<1000; i++) { ????? int t = 0; ????? for(int j=1; j<= i/2; j++) { ?????? if(i % j == 0) { ??????? t = t + j; ?????? } ????? } ????? if(t == i) { ?????? System.out.print(i + "???? "); ????? } ???? } }
}
【程序10】??? 題目：一球從100米高度自由落下，每次落地后反跳回原高度的一半；再落下，求它在?第10次落地時(shí)，共經(jīng)過(guò)多少米？第10次反彈多高？ public?class?lianxi10 {
public?static?void?main(String[] args) {
??????double?h = 100,s = 0;
??????for(int?i=1; i<=10; i++) {
??????s = s + 2*h;
??????h = h / 2;
?????}
??????s=s-100;
?????System.out.println("經(jīng)過(guò)路程："?+ s);
?????System.out.println("最后高度："?+ h);
?????
}
} ? 【程序11】??? 題目：有1、2、3、4四個(gè)數(shù)字，能組成多少個(gè)互不相同且一個(gè)數(shù)字中無(wú)重復(fù)數(shù)字的三位數(shù)？并把他們都輸入。??? public class lianxi11 { public static void main(String[] args) { ???? int count = 0; ???? for(int x=1; x<5; x++) { ????? for(int y=1; y<5; y++) { ?????? for(int z=1; z<5; z++) { ??????? if(x != y && y != z && x != z) { ???????? count ++; ???????? System.out.println(x*100 + y*10 + z ); ??????? } ?????? } ????? } ???? } ???? System.out.println("共有" + count + "個(gè)三位數(shù)"); } } 【程序12】??? 題目：企業(yè)發(fā)放的獎(jiǎng)金根據(jù)利潤(rùn)提成。利潤(rùn)(I)低于或等于10萬(wàn)元時(shí)，獎(jiǎng)金可提10%；利潤(rùn)高于10萬(wàn)元，低于20萬(wàn)元時(shí)，低于10萬(wàn)元的部分按10%提成，高于10萬(wàn)元的部分，可可提成7.5%；20萬(wàn)到40萬(wàn)之間時(shí)，高于20萬(wàn)元的部分，可提成5%；40萬(wàn)到60萬(wàn)之間時(shí)高于40萬(wàn)元的部分，可提成3%；60萬(wàn)到100萬(wàn)之間時(shí)，高于60萬(wàn)元的部分，可提成1.5%，高于100萬(wàn)元時(shí)，超過(guò)100萬(wàn)元的部分按1%提成，從鍵盤輸入當(dāng)月利潤(rùn)，求應(yīng)發(fā)放獎(jiǎng)金總數(shù)？??? import java.util.*; public class lianxi12 { public static void main(String[] args) { ???? double x = 0,y = 0; ???? System.out.print("輸入當(dāng)月利潤(rùn)（萬(wàn)）："); ???? Scanner s = new Scanner(System.in); ???? x = s.nextInt(); ???? if(x > 0 && x <= 10) { ???? y = x * 0.1; ???? } else if(x > 10 && x <= 20) { ????? y = 10 * 0.1 + (x - 10) * 0.075; ???? } else if(x > 20 && x <= 40) { ????? y = 10 * 0.1 + 10 * 0.075 + (x - 20) * 0.05; ???? } else if(x > 40 && x <= 60) { ????? y = 10 * 0.1 + 10 * 0.075 + 20 * 0.05 + (x - 40) * 0.03; ???? } else if(x > 60 && x <= 100) { ????? y = 20 * 0.175 + 20 * 0.05 + 20 * 0.03 + (x - 60) * 0.015; ???? } else if(x > 100) { ????? y = 20 * 0.175 + 40 * 0.08 + 40 * 0.015 + (x - 100) * 0.01; ???? } ???? System.out.println("應(yīng)該提取的獎(jiǎng)金是 " + y + "萬(wàn)"); } }
【程序13】??? 題目：一個(gè)整數(shù)，它加上100后是一個(gè)完全平方數(shù)，再加上168又是一個(gè)完全平方數(shù)，請(qǐng)問(wèn)該數(shù)是多少？??? public class lianxi13 { public static void main(String[] args) { ???? for(int x =1; x<100000; x++) { ????? if(Math.sqrt(x+100) % 1 == 0) { ?????? if(Math.sqrt(x+168) % 1 == 0) { ??????? System.out.println(x + "加100是一個(gè)完全平方數(shù)，再加168又是一個(gè)完全平方數(shù)"); ?????? } ????? } ???? } } } /*按題意循環(huán)應(yīng)該從-100開始（整數(shù)包括正整數(shù)、負(fù)整數(shù)、零），這樣會(huì)多一個(gè)滿足條件的數(shù)-99。 但是我看到大部分人解這道題目時(shí)都把題中的“整數(shù)”理解成正整數(shù)，我也就隨大流了。*/
【程序14】?? 題目：輸入某年某月某日，判斷這一天是這一年的第幾天？??? import java.util.*; public class lianxi14 { public static void main(String[] args) { ???? int year, month, day; ???? int days = 0; ???? int d = 0; ???? int e; ???? input fymd = new input(); ???? do { ???? e = 0; ???? System.out.print("輸入年："); ???? year =fymd.input(); ???? System.out.print("輸入月："); ???? month = fymd.input(); ???? System.out.print("輸入天："); ???? day = fymd.input(); ???? if (year < 0 || month < 0 || month > 12 || day < 0 || day > 31) { ???? System.out.println("輸入錯(cuò)誤，請(qǐng)重新輸入！"); ???? e=1 ; ???? } ???? }while( e==1);
????? for (int i=1; i <month; i++) { ????? switch (i) { ????? case 1: ????? case 3: ????? case 5: ????? case 7: ????? case 8: ????? case 10: ????? case 12: ?????? days = 31; ????? break; ????? case 4: ????? case 6: ????? case 9: ????? case 11: ?????? days = 30; ????? break; ????? case 2: ?????? if ((year % 400 == 0) || (year % 4 == 0 && year % 100 != 0)) { ??????? days = 29; ?????? } else { ??????? days = 28; ?????? } ?????? break; ????? } ????? d += days; ????? } ???? System.out.println(year + "-" + month + "-" + day + "是這年的第" + (d+day) + "天。"); } } class input{ public int input() { ???? int value = 0; ???? Scanner s = new Scanner(System.in); ???? value = s.nextInt(); ???? return value; } }
【程序15】??? 題目：輸入三個(gè)整數(shù)x,y,z，請(qǐng)把這三個(gè)數(shù)由小到大輸出。??? import java.util.*; public class lianxi15 { public static void main(String[] args) { ???? input fnc = new input(); ???? int x=0, y=0, z=0; ???? System.out.print("輸入第一個(gè)數(shù)字："); ????? x = fnc.input(); ???? System.out.print("輸入第二個(gè)數(shù)字："); ????? y = fnc.input(); ???? System.out.print("輸入第三個(gè)數(shù)字："); ????? z = fnc.input();??? ??? if(x > y) { ????? int t = x; ????? x = y; ????? y = t; ???? } ??? if(x > z) { ????? int t = x; ????? x = z; ????? z = t; ???? } ??? if(y > z) { ????? int t = y; ????? y = z; ????? z = t; ???? } ??? System.out.println( "三個(gè)數(shù)字由小到大排列為： "+x + " " + y + " " + z); } } class input{ public int input() { ???? int value = 0; ???? Scanner s = new Scanner(System.in); ???? value = s.nextInt(); ???? return value; } } 【程序16】 題目：輸出9*9口訣。????? public class lianxi16 { public static void main(String[] args) { ???? for(int i=1; i<10; i++) { ????? for(int j=1; j<=i; j++) { ?????? System.out.print(j + "*" + i + "=" + j*i + "??? " ); ???????? if(j*i<10){System.out.print(" ");} } ????????? System.out.println(); ???? } } } 【程序17】??? 題目：猴子吃桃問(wèn)題：猴子第一天摘下若干個(gè)桃子，當(dāng)即吃了一半，還不癮，又多吃了一個(gè)???? 第二天早上又將剩下的桃子吃掉一半，又多吃了一個(gè)。以后每天早上都吃了前一天剩下???? 的一半零一個(gè)。到第10天早上想再吃時(shí)，見只剩下一個(gè)桃子了。求第一天共摘了多少。??? public class lianxi17 { public static void main(String[] args) { ???? int x = 1; ???? for(int i=2; i<=10; i++) { ????? x = (x+1)*2; ???? } ???? System.out.println("猴子第一天摘了 " + x + " 個(gè)桃子"); } }
【程序18】??? 題目：兩個(gè)乒乓球隊(duì)進(jìn)行比賽，各出三人。甲隊(duì)為a,b,c三人，乙隊(duì)為x,y,z三人。已抽簽決定比賽名單。有人向隊(duì)員打聽比賽的名單。a說(shuō)他不和x比，c說(shuō)他不和x,z比，請(qǐng)編程序找出三隊(duì)賽手的名單。??? public class lianxi18 {
static char[] m = { 'a', 'b', 'c' }; static char[] n = { 'x', 'y', 'z' };
public static void main(String[] args) {
?? for (int i = 0; i < m.length; i++) { ??? for (int j = 0; j < n.length; j++) {
???? if (m[i] == 'a' && n[j] == 'x') {
????? continue;
} else if (m[i] == 'a' && n[j] == 'y') {
????? continue;
???? } else if ((m[i] == 'c' && n[j] == 'x')
?????? || (m[i] == 'c' && n[j] == 'z')) {
????? continue;
???? } else if ((m[i] == 'b' && n[j] == 'z')
?????? || (m[i] == 'b' && n[j] == 'y')) {
????? continue;
???? } else
????? System.out.println(m[i] + " vs " + n[j]);
??? }
?? }
}
}
【程序19】??? 題目：打印出如下圖案（菱形）??? ???? *??? ?? ***??? ?*****??? *******??? ?*****??? ?? ***??? ??? *??? public class lianxi19 { public static void main(String[] args) { ??? int H = 7, W = 7;//高和寬必須是相等的奇數(shù) ??? for(int i=0; i<(H+1) / 2; i++) { ???? for(int j=0; j<W/2-i; j++) { ????? System.out.print(" ");
???? } ???? for(int k=1; k<(i+1)*2; k++) { ????? System.out.print('*'); ???? } ???? System.out.println(); ??? } ??? for(int i=1; i<=H/2; i++) { ???? for(int j=1; j<=i; j++) { ????? System.out.print(" "); ???? } ???? for(int k=1; k<=W-2*i; k++) { ????? System.out.print('*'); ???? } ???? System.out.println(); ??? } } }
【程序20】??? 題目：有一分?jǐn)?shù)序列：2/1，3/2，5/3，8/5，13/8，21/13...求出這個(gè)數(shù)列的前20項(xiàng)之和。?
public class lianxi20 { public static void main(String[] args) { ??? int x = 2, y = 1, t; ??? double sum = 0; ??? for(int i=1; i<=20; i++) { ???? sum = sum + (double)x / y; ???? t = y; ???? y = x; ???? x = y + t; ???? } System.out.println("前20項(xiàng)相加之和是： " + sum); } }
【程序21】??? 題目：求1+2!+3!+...+20!的和??? public class lianxi21 { public static void main(String[] args) { ??? long sum = 0; ??? long fac = 1; ??? for(int i=1; i<=20; i++) { ???? fac = fac * i; ???? sum += fac; ??? } ??? System.out.println(sum); }
}
【程序22】??? 題目：利用遞歸方法求5!。??? public class lianxi22 { public static void main(String[] args) { ?????? int n = 5; ??? rec fr = new rec(); ??? System.out.println(n+"! = "+fr.rec(n)); } } class rec{ public long rec(int n) { ??? long value = 0 ; ??? if(n ==1 ) { ???? value = 1; ??? } else?? { ???? value = n * rec(n-1); ??? } ??? return value; } }
【程序23】??? 題目：有5個(gè)人坐在一起，問(wèn)第五個(gè)人多少歲？他說(shuō)比第4個(gè)人大2歲。問(wèn)第4個(gè)人歲數(shù)，他說(shuō)比第3個(gè)人大2歲。問(wèn)第三個(gè)人，又說(shuō)比第2人大兩歲。問(wèn)第2個(gè)人，說(shuō)比第一個(gè)人大兩歲。最后問(wèn)第一個(gè)人，他說(shuō)是10歲。請(qǐng)問(wèn)第五個(gè)人多大？???
public class lianxi23 { public static void main(String[] args) { ??? int age = 10; ???? for(int i=2; i<=5; i++) { ???? age =age+2; ??? } ??? System.out.println(age); } }
【程序24】??? 題目：給一個(gè)不多于5位的正整數(shù)，要求：一、求它是幾位數(shù)，二、逆序打印出各位數(shù)字。??? //使用了長(zhǎng)整型最多輸入18位 import java.util.*; public class lianxi24 { public static void main(String[] args) { ?? Scanner s = new Scanner(System.in); ?? System.out.print("請(qǐng)輸入一個(gè)正整數(shù)："); ?? long a = s.nextLong(); ?? String ss = Long.toString(a); ??? char[] ch = ss.toCharArray(); ??? int j=ch.length; ??? System.out.println(a + "是一個(gè)"+ j +"位數(shù)。"); ??? System.out.print("按逆序輸出是："); ??? for(int i=j-1; i>=0; i--) { ??? System.out.print(ch[i]); ?? } ?? } ?? }
【程序25】??? 題目：一個(gè)5位數(shù)，判斷它是不是回文數(shù)。即12321是回文數(shù)，個(gè)位與萬(wàn)位相同，十位與千位相同。??? import java.util.*; public class lianxi25 { public static void main(String[] args) { ??? Scanner s = new Scanner(System.in); ??? int a; ??? do{ ???? System.out.print("請(qǐng)輸入一個(gè)5位正整數(shù)："); ????? a = s.nextInt(); ????? }while(a<10000||a>99999); ???? String ss =String.valueOf(a); ???? char[] ch = ss.toCharArray(); ???? if(ch[0]==ch[4]&&ch[1]==ch[3]){ ???? System.out.println("這是一個(gè)回文數(shù)");} ???? else {System.out.println("這不是一個(gè)回文數(shù)");} ??? } ??? } //這個(gè)更好，不限位數(shù) import java.util.*; public class lianxi25a { public static void main(String[] args) { ?? Scanner s = new Scanner(System.in); ?? boolean is =true; ?? System.out.print("請(qǐng)輸入一個(gè)正整數(shù)："); ?? long a = s.nextLong(); ?? String ss = Long.toString(a); ?? char[] ch = ss.toCharArray(); ?? int j=ch.length; ?? for(int i=0; i<j/2; i++) { ?? if(ch[i]!=ch[j-i-1]){is=false;} ?? } ?? if(is==true){System.out.println("這是一個(gè)回文數(shù)");} ???? else {System.out.println("這不是一個(gè)回文數(shù)");} ??? } ?? }
【程序26】??? 題目：請(qǐng)輸入星期幾的第一個(gè)字母來(lái)判斷一下是星期幾，如果第一個(gè)字母一樣，則繼續(xù)?? 判斷第二個(gè)字母。??? import java.util.*; public class lianxi26 { public static void main(String[] args) { ??? getChar tw = new getChar(); ??? System.out.println("請(qǐng)輸入星期的第一個(gè)大寫字母："); ??? char ch = tw.getChar(); ??? switch(ch) { ???? case 'M': ????? System.out.println("Monday"); ????? break; ???? case 'W': ????? System.out.println("Wednesday"); ????? break; ???? case 'F': ????? System.out.println("Friday"); ????? break; ???? case 'T': { ????? System.out.println("請(qǐng)輸入星期的第二個(gè)字母："); ????? char ch2 = tw.getChar(); ????? if(ch2 == 'U') {System.out.println("Tuesday"); } ????? else if(ch2 == 'H') {System.out.println("Thursday"); } ????? else {System.out.println("無(wú)此寫法！"); ?????? } ???? }; ????? break; ???? case 'S': { ?????? System.out.println("請(qǐng)輸入星期的第二個(gè)字母："); ????? char ch2 = tw.getChar(); ????? if(ch2 == 'U') {System.out.println("Sunday"); } ?????? else if(ch2 == 'A') {System.out.println("Saturday"); } ?????? else {System.out.println("無(wú)此寫法！"); ?????? } ???? }; ????? break; default:System.out.println("無(wú)此寫法！"); } ?? } } class getChar{ public char getChar() { ??? Scanner s = new Scanner(System.in); ??? String str = s.nextLine(); ??? char ch = str.charAt(0); ??? if(ch<'A' || ch>'Z') { ???? System.out.println("輸入錯(cuò)誤，請(qǐng)重新輸入"); ???? ch=getChar(); ??? } ??? return ch; } }??
【程序27】??? 題目：求100之內(nèi)的素?cái)?shù)??? //使用除sqrt(n)的方法求出的素?cái)?shù)不包括2和3 public class lianxi27 { public static void main(String[] args) { ??? boolean b =false; ??? System.out.print(2 + " "); ??? System.out.print(3 + " "); ??? for(int i=3; i<100; i+=2) { ???? for(int j=2; j<=Math.sqrt(i); j++) { ????? if(i % j == 0) {b = false; ????????????????????? break; ?????? } else{b = true;} ???? } ?? if(b == true) {System.out.print(i + " ");} ??? } ?? } } //該程序使用除1位素?cái)?shù)得2位方法，運(yùn)行效率高通用性差。 public class lianxi27a { public static void main(String[] args) { ??? int[] a = new int[]{2, 3, 5, 7}; ?? for(int j=0; j<4; j++)System.out.print(a[j] + " "); ??? boolean b =false; ??? for(int i=11; i<100; i+=2) { ???? for(int j=0; j<4; j++) { ????? if(i % a[j] == 0) {b = false; ????????????????????? break; ?????? } else{b = true;} ???? } ?? if(b == true) {System.out.print(i + " ");} ??? } ?? } }
【程序28】??? 題目：對(duì)10個(gè)數(shù)進(jìn)行排序??? import java.util.*; public class lianxi28 { public static void main(String[] args) { Scanner s = new Scanner(System.in); ?? int[] a = new int[10]; ?? System.out.println("請(qǐng)輸入10個(gè)整數(shù)："); ?? for(int i=0; i<10; i++) { ??? a[i] = s.nextInt(); ?? }
?? for(int i=0; i<10; i++) { ??? for(int j=i+1; j<10; j++) { ???? if(a[i] > a[j]) { ????? int t = a[i]; ????? a[i] = a[j]; ????? a[j] = t; ???? } ??? } ?? } ?? for(int i=0; i<10; i++) { ??? System.out.print(a[i] + " "); ?? } } }
【程序29】??? 題目：求一個(gè)3*3矩陣對(duì)角線元素之和?
???? import java.util.*; public class lianxi29 { public static void main(String[] args) { ?? Scanner s = new Scanner(System.in); ?? int[][] a = new int[3][3]; System.out.println("請(qǐng)輸入9個(gè)整數(shù)："); ?? for(int i=0; i<3; i++) { ??? for(int j=0; j<3; j++) { ???? a[i][j] = s.nextInt(); ??? } ?? } ?? System.out.println("輸入的3 * 3 矩陣是:"); ?? for(int i=0; i<3; i++) { ??? for(int j=0; j<3; j++) { ???? System.out.print(a[i][j] + " "); ??? } ??? System.out.println(); ?? } ?? int sum = 0; ?? for(int i=0; i<3; i++) { ??? for(int j=0; j<3; j++) { ???? if(i == j) { ????? sum += a[i][j]; ???? } ??? } ?? } ?? System.out.println("對(duì)角線之和是：" + sum); } }
【程序30】??? 題目：有一個(gè)已經(jīng)排好序的數(shù)組?，F(xiàn)輸入一個(gè)數(shù)，要求按原來(lái)的規(guī)律將它插入數(shù)組中。???? //此程序不好，沒(méi)有使用折半查找插入
import?java.util.*;
public?class?lianxi30?{
public?static?void?main(String[] args) {
???int[] a = new?int[]{1, 2, 6, 14, 25, 36, 37,55};
???int[] b = new?int[a.length+1];
??int?t1=0, t2 = 0; ??????????????????????????????????????????
???int?i =0;
???Scanner s= new?Scanner(System.in);
???System.out.print("請(qǐng)輸入一個(gè)整數(shù)：");
???int?num = s.nextInt();
???if(num >= a[a.length-1]) {
????b[b.length-1] = num;
????for(i=0; i<a.length; i++) {
?????b[i] = a[i];
????}
???} else?{
????for(i=0; i<a.length; i++) {
?????if(num >= a[i]) {
??????b[i] = a[i];
?????} else?{ ????
??????b[i] = num;
??????break;
?????}
????}
????for(int?j=i+1; j<b.length; j++) {
?????b[j] = a[j-1];
????}
???}
???for?(i = 0; i < b.length; i++) {
????System.out.print(b[i] + " ");
???}
} ??????????????????????????????????????
}
【程序31】 題目：將一個(gè)數(shù)組逆序輸出。?
?? import java.util.*; public class lianxi31 { public static void main(String[] args) { ?? Scanner s = new Scanner(System.in); ?? int a[] = new int[20]; System.out.println("請(qǐng)輸入多個(gè)正整數(shù)（輸入-1表示結(jié)束）："); ?? int i=0,j;?? do{ ?? ?? a[i]=s.nextInt(); ?? ?? i++; ?? }while (a[i-1]!=-1);
?? System.out.println("你輸入的數(shù)組為："); ?? for( j=0; j<i-1; j++) { ??? System.out.print(a[j]+"?? "); } ?? System.out.println("\n數(shù)組逆序輸出為："); ?? for( j=i-2; j>=0; j=j-1) { ??? System.out.print(a[j]+"?? "); } ??? } ?? } 【程序32】??? 題目：取一個(gè)整數(shù)a從右端開始的4～7位。??? import java.util.*; public class lianxi32 { public static void main(String[] args) { ??? Scanner s = new Scanner(System.in); ??? System.out.print("請(qǐng)輸入一個(gè)7位以上的正整數(shù)："); ??? long a = s.nextLong(); ??? String ss = Long.toString(a); ??? char[] ch = ss.toCharArray(); ??? int j=ch.length; ??? if (j<7){System.out.println("輸入錯(cuò)誤！");} ??? else { ???? System.out.println("截取從右端開始的4～7位是："+ch[j-7]+ch[j-6]+ch[j-5]+ch[j-4]); ???? } ??? } ??? } 【程序33】?? 題目：打印出楊輝三角形（要求打印出10行如下圖）?????? ??????????? 1??? ????????? 1??? 1??? ??????? 1??? 2??? 1??? ????? 1??? 3??? 3??? 1??? ??? 1??? 4??? 6??? 4??? 1??? 1??? 5??? 10??? 10??? 5??? 1??? ………… public class lianxi33 { public static void main(String[] args) { ??? int[][] a = new int[10][10]; ?? for(int i=0; i<10; i++) { ??? a[i][i] = 1; ??? a[i][0] = 1; ?? } ?? for(int i=2; i<10; i++) { ??? for(int j=1; j<i; j++) { ???? a[i][j] = a[i-1][j-1] + a[i-1][j]; ??? } ?? } ???? for(int i=0; i<10; i++) { ??? for(int k=0; k<2*(10-i)-1; k++) { ???? System.out.print(" "); ??? } ??? for(int j=0; j<=i; j++) { ???? System.out.print(a[i][j] + "?? "); ??? } ??? System.out.println(); ?? } } } 【程序34】??? 題目：輸入3個(gè)數(shù)a,b,c，按大小順序輸出。??? import java.util.Scanner; public class lianxi34 { public static void main(String[] args) { ??? Scanner s = new Scanner(System.in); ??? System.out.println("請(qǐng)輸入3個(gè)整數(shù)："); ??? int a = s.nextInt(); ??? int b = s.nextInt(); ??? int c = s.nextInt(); ????? if(a < b) { ???? int t = a; ???? a = b; ???? b = t; ??? } ????? if(a < c) { ???? int t = a; ???? a = c; ???? c = t; ??? } ???? if(b < c) { ???? int t = b; ???? b = c; ???? c = t; ??? } ??? System.out.println("從大到小的順序輸出:"); ??? System.out.println(a + " " + b + " " + c); } } 【程序35】??? 題目：輸入數(shù)組，最大的與第一個(gè)元素交換，最小的與最后一個(gè)元素交換，輸出數(shù)組。???
import?java.util.*;
public?class?lianxi35 {
public?static?void?main(String[] args) {
int?N = 8;
int[] a = new?int[N];// 創(chuàng)建一個(gè)八個(gè)元素的數(shù)組
Scanner s = new?Scanner(System.in);
int?idx1 = 0, idx2 = 0;
System.out.println("請(qǐng)輸入8個(gè)整數(shù)：");
for?(int?i = 0; i < N; i++) {
a[i] = s.nextInt();
}
// 獲得輸入的八個(gè)數(shù)字
System.out.println("你輸入的數(shù)組為：");
for?(int?i = 0; i < N; i++) {
System.out.print(a[i] + " ");
}
// 輸出輸入的數(shù)組
int?max = a[0], min = a[0];
for?(int?i = 0; i < N; i++) {
if?(a[i] > max) {
max = a[i];
idx1 = i;
}
// 找出最大的數(shù)和其下標(biāo)
if?(a[i] < min) {
min = a[i];
idx2 = i;
}// 找出最大的數(shù)和其下標(biāo)
}
?
if?(idx1 != 0) {
int?temp = a[0];
a[0] = a[idx1];
a[idx1] = temp;
}// 最大的數(shù)和第一個(gè)數(shù)交換位置
if?(idx2 != N - 1) {
int?temp = a[N - 1];
a[N - 1] = a[idx2];
a[idx2] = temp;
}// 最小的數(shù)和最后一個(gè)數(shù)交換位置
?
System.out.println("\n交換后的數(shù)組為：");
for?(int?i = 0; i < N; i++) {
System.out.print(a[i] + " ");
}
}
}
【程序36】??? 題目：有n個(gè)整數(shù)，使其前面各數(shù)順序向后移m個(gè)位置，最后m個(gè)數(shù)變成最前面的m個(gè)數(shù)??? import java.util.Scanner; public class lianxi36 { public static void main(String[] args) { ?? int N =10; ?? int[] a = new int[N]; ?? Scanner s = new Scanner(System.in); ?? System.out.println("請(qǐng)輸入10個(gè)整數(shù)："); ?? for(int i=0; i<N; i++) { ??? a[i] = s.nextInt(); ?? } ?? System.out.print("你輸入的數(shù)組為："); ?? for(int i=0; i<N; i++) { ???? System.out.print(a[i] + " "); ?? } ?? System.out.print("\n請(qǐng)輸入向后移動(dòng)的位數(shù)："); ?? int m = s.nextInt(); ?? int[] b = new int[m]; ?? for(int i=0; i<m; i++) { ??? b[i] = a[N-m+i]; ?? } ?? for(int i=N-1; i>=m; i--) { ?? a[i] = a[i-m]; ?? } ?? for(int i=0; i<m; i++) { ??? a[i] = b[i]; ?? } System.out.print("位移后的數(shù)組是："); ?? for(int i=0; i<N; i++) { ??? System.out.print(a[i] + " "); ?? } } } 【程序37】??? 題目：有n個(gè)人圍成一圈，順序排號(hào)。從第一個(gè)人開始報(bào)數(shù)（從1到3報(bào)數(shù)），凡報(bào)到3的人退出圈子，問(wèn)最后留下的是原來(lái)第幾號(hào)的那位。??? import java.util.Scanner; public class lianxi37 { public static void main(String[] args) { ?? Scanner s = new Scanner(System.in); ?? System.out.print("請(qǐng)輸入排成一圈的人數(shù)："); ?? int n = s.nextInt(); ?? boolean[] arr = new boolean[n]; ?? for(int i=0; i<arr.length; i++) { ??? arr[i] = true; ?? }//數(shù)組賦值都是true ?? int leftCount = n; ?? int countNum = 0; ?? int index = 0; ?? while(leftCount > 1) { ??? if(arr[index] == true) { ???? countNum ++; ???? if(countNum == 3) { ????? countNum =0; ????? arr[index] = false; ????? leftCount --; ???? } ??? } ???? index ++; ???? if(index == n) { ???? index = 0; ??? } ?? } ??? for(int i=0; i<n; i++) { ??? if(arr[i] == true) { ???? System.out.println("原排在第"+(i+1)+"位的人留下了。"); ??? } ?? } } } 【程序38】??? 題目：寫一個(gè)函數(shù)，求一個(gè)字符串的長(zhǎng)度，在main函數(shù)中輸入字符串，并輸出其長(zhǎng)度。??? /*……………… *……題目意思似乎不能用length()函數(shù)???? */ import java.util.*; public class lianxi38 { public static void main(String[] args) { ??? Scanner s = new Scanner(System.in); ??? System.out.println("請(qǐng)輸入一個(gè)字符串："); ??? String str = s.nextLine(); ???? System.out.println("字符串的長(zhǎng)度是："+str.length()); ??? } ??? } 【程序39】??? 題目：編寫一個(gè)函數(shù)，輸入n為偶數(shù)時(shí)，調(diào)用函數(shù)求1/2+1/4+...+1/n,當(dāng)輸入n為奇數(shù)時(shí)，調(diào)用函數(shù)1/1+1/3+...+1/n(利用指針函數(shù))??? //沒(méi)有利用指針函數(shù) import java.util.*; public class lianxi39 { public static void main(String[] args) { ??? Scanner s = new Scanner(System.in); ??? System.out.print("請(qǐng)輸入一個(gè)正整數(shù) n= "); ??? int n = s.nextInt(); ??? System.out.println("相應(yīng)數(shù)列的和為：" + sum(n)); ?? } public static double sum(int n) { ??? double res = 0; ??? if(n % 2 == 0) { ???? for(int i=2; i<=n; i+=2) { ????? res += (double)1 / i; ???? } ??? } else { ???? for(int i=1; i<=n; i+=2) { ????? res += (double)1 / i ; ???? } ??? } ??? return res; } } 【程序40】??? 題目：字符串排序。??? public class lianxi40 { public static void main(String[] args) { ?? int N=5; ?? String temp = null; ?? String[] s = new String[N]; ?? s[0] = "matter"; ?? s[1] = "state"; ?? s[2] = "solid"; ?? s[3] = "liquid"; ?? s[4] = "gas"; ?? for(int i=0; i<N; i++) { ??? for(int j=i+1; j<N; j++) { ???? if(compare(s[i], s[j]) == false) { ????? temp = s[i]; ????? s[i] = s[j]; ????? s[j] = temp; ???? } ??? } ?? } ??? for(int i=0; i<N; i++) { ??? System.out.println(s[i]); ?? } } static boolean compare(String s1, String s2) { ?? boolean result = true; ?? for(int i=0; i<s1.length() && i<s2.length(); i++) { ??? if(s1.charAt(i) > s2.charAt(i)) { ???? result = false; ???? break; ??? } else if(s1.charAt(i) <s2.charAt(i)) { ???? result = true; ???? break; ??? } else { ???? if(s1.length() < s2.length()) { ????? result = true; ???? } else { ????? result = false; ???? } ??? } ?? } ?? return result; } } 【程序41】???題目：海灘上有一堆桃子，五只猴子來(lái)分。第一只猴子把這堆桃子憑據(jù)分為五份，多了一個(gè)，這只猴子把多的一個(gè)扔入海中，拿走了一份。第二只猴子把剩下的桃子又平均分成五份，又多了一個(gè)，它同樣把多的一個(gè)扔入海中，拿走了一份，第三、第四、第五只猴子都是這樣做的，問(wèn)海灘上原來(lái)最少有多少個(gè)桃子？??? public class lianxi41 { public static void main (String[] args) { int i,m,j=0,k,count; for(i=4;i<10000;i+=4) ?? { count=0; ???? m=i; ???? for(k=0;k<5;k++) ??????? { ???????? j=i/4*5+1; ???????? i=j; ???????? if(j%4==0) ??????????? count++; ??????????? else break; ?????? } ??? i=m; if(count==4) {System.out.println("原有桃子 "+j+" 個(gè)"); break;} } } } 【程序42】??? 題目：809*??=800*??+9*??+1??? 其中??代表的兩位數(shù),8*??的結(jié)果為兩位數(shù)，9*??的結(jié)果為3位數(shù)。求??代表的兩位數(shù)，及809*??后的結(jié)果。??? //題目錯(cuò)了！809x=800x+9x+1 這樣的方程無(wú)解。去掉那個(gè)1就有解了。 public class lianxi42 { public static void main (String[] args) { int a=809,b,i; for(i=10;i<13;i++) {b=i*a ; if(8*i<100&&9*i>=100) System.out.println ("809*"+i+"="+"800*"+i+"+"+"9*"+i+"="+b);} } } 【程序43】??? 題目：求0—7所能組成的奇數(shù)個(gè)數(shù)。??? //組成1位數(shù)是4個(gè)。 //組成2位數(shù)是7*4個(gè)。 //組成3位數(shù)是7*8*4個(gè)。 //組成4位數(shù)是7*8*8*4個(gè)。 //...... public class lianxi43 { public static void main (String[] args) { int sum=4; int j; System.out.println("組成1位數(shù)是 "+sum+" 個(gè)"); sum=sum*7; System.out.println("組成2位數(shù)是 "+sum+" 個(gè)"); for(j=3;j<=9;j++){ sum=sum*8; System.out.println("組成"+j+"位數(shù)是 "+sum+" 個(gè)"); } } } 【程序44】??? 題目：一個(gè)偶數(shù)總能表示為兩個(gè)素?cái)?shù)之和。??? //由于用除sqrt(n)的方法求出的素?cái)?shù)不包括2和3， //因此在判斷是否是素?cái)?shù)程序中人為添加了一個(gè)3。 import java.util.*; public class lianxi44 { public static void main(String[] args) { Scanner s = new Scanner(System.in); int n,i; do{ ???? System.out.print("請(qǐng)輸入一個(gè)大于等于6的偶數(shù)："); ???? n = s.nextInt(); ??? } while(n<6||n%2!=0);?? //判斷輸入是否是>=6偶數(shù),不是,重新輸入 fun fc = new fun(); ??? for(i=2;i<=n/2;i++){ ??? if((fc.fun(i))==1&&(fc.fun(n-i)==1)) ??? {int j=n-i; ???? System.out.println(n+" = "+i+" + "+j); ???? } //輸出所有可能的素?cái)?shù)對(duì) ?? } } } class fun{ public int fun (int a)??? //判斷是否是素?cái)?shù)的函數(shù) { int i,flag=0; if(a==3){flag=1;return(flag);} for(i=2;i<=Math.sqrt(a);i++){ ?? if(a%i==0) {flag=0;break;} ????? else flag=1;} return (flag) ;//不是素?cái)?shù),返回0,是素?cái)?shù),返回1 } } //解法二 import java.util.*; public class lianxi44 { public static void main(String[] args) { Scanner s = new Scanner(System.in); int n; do{ ???? System.out.print("請(qǐng)輸入一個(gè)大于等于6的偶數(shù)："); ???? n = s.nextInt(); ??? } while(n<6||n%2!=0);?? //判斷輸入是否是>=6偶數(shù),不是,重新輸入
??? for(int i=3;i<=n/2;i+=2){ ??? if(fun(i)&&fun(n-i)) { ????? System.out.println(n+" = "+i+" + "+(n-i)); ????? } //輸出所有可能的素?cái)?shù)對(duì) ?? } } static boolean fun (int a){??? //判斷是否是素?cái)?shù)的函數(shù) boolean flag=false; if(a==3){flag=true;return(flag);} for(int i=2;i<=Math.sqrt(a);i++){ ?? if(a%i==0) {flag=false;break;} ????? else flag=true;} return (flag) ; } } 【程序45】??? 題目：判斷一個(gè)素?cái)?shù)能被幾個(gè)9整除??? //題目錯(cuò)了吧？能被9整除的就不是素?cái)?shù)了！所以改成整數(shù)了。 import java.util.*; public class lianxi45 { public static void main (String[] args) { ?? Scanner s = new Scanner(System.in); ?? System.out.print("請(qǐng)輸入一個(gè)整數(shù)："); ??? int num = s.nextInt(); ??? int?? tmp = num; ??? int count = 0; ?????? for(int i = 0 ; tmp%9 == 0 ;){ ?????????? tmp = tmp/9; ??????????? count ++; ????????? } ???? System.out.println(num+" 能夠被 "+count+" 個(gè)9整除。"); ???? } } 【程序46】??? 題目：兩個(gè)字符串連接程序??? import java.util.*; public class lianxi46 { public static void main(String[] args) { ??? Scanner s = new Scanner(System.in); ??? System.out.print("請(qǐng)輸入一個(gè)字符串："); ??? String str1 = s.nextLine(); ??? System.out.print("請(qǐng)?jiān)佥斎胍粋€(gè)字符串："); ??? String str2 = s.nextLine(); ??? String str = str1+str2; ??? System.out.println("連接后的字符串是："+str); ??? } ??? } 【程序47】??? 題目：讀取7個(gè)數(shù)（1—50）的整數(shù)值，每讀取一個(gè)值，程序打印出該值個(gè)數(shù)的＊。??? import java.util.*; public class lianxi47 { public static void main(String[] args) { Scanner s = new Scanner(System.in); int n=1,num; while(n<=7){ ???????? do{ ????????? System.out.print("請(qǐng)輸入一個(gè)1--50之間的整數(shù)："); ???????????? num= s.nextInt(); ?????????? }while(num<1||num>50); ????? for(int i=1;i<=num;i++) ????? {System.out.print("*"); ????? } System.out.println(); n ++; } } } 【程序48】??? 題目：某個(gè)公司采用公用電話傳遞數(shù)據(jù)，數(shù)據(jù)是四位的整數(shù)，在傳遞過(guò)程中是加密的，加密規(guī)則如下：每位數(shù)字都加上5,然后用和除以10的余數(shù)代替該數(shù)字，再將第一位和第四位交換，第二位和第三位交換。??? import java.util.*; public class lianxi48?? { public static void main(String args[]) { Scanner s = new Scanner(System.in); int num=0,temp; do{ ?? System.out.print("請(qǐng)輸入一個(gè)4位正整數(shù)："); ????? num = s.nextInt(); ???? }while (num<1000||num>9999); int a[]=new int[4]; a[0] = num/1000; //取千位的數(shù)字 a[1] = (num/100)%10; //取百位的數(shù)字 a[2] = (num/10)%10; //取十位的數(shù)字 a[3] = num%10; //取個(gè)位的數(shù)字 for(int j=0;j<4;j++) { a[j]+=5; a[j]%=10; } for(int j=0;j<=1;j++) ??? { ??? temp = a[j]; ??? a[j] = a[3-j]; ??? a[3-j] =temp; ??? } System.out.print("加密后的數(shù)字為："); for(int j=0;j<4;j++) System.out.print(a[j]); } } 【程序49】??? 題目：計(jì)算字符串中子串出現(xiàn)的次數(shù)??? import java.util.*; public class lianxi49 { public static void main(String args[]){ Scanner s = new Scanner(System.in); ??? System.out.print("請(qǐng)輸入字符串："); ??? String str1 = s.nextLine(); ??? System.out.print("請(qǐng)輸入子串："); ??? String str2 = s.nextLine(); int count=0; if(str1.equals("")||str2.equals("")) ?? { ?? System.out.println("你沒(méi)有輸入字符串或子串,無(wú)法比較!"); ?? System.exit(0); ?? } else ?? { ??? for(int i=0;i<=str1.length()-str2.length();i++) ???? { ???? if(str2.equals(str1.substring(i, str2.length()+i))) ????? //這種比法有問(wèn)題，會(huì)把"aaa"看成有2個(gè)"aa"子串。 ?????? count++; ?????? } System.out.println("子串在字符串中出現(xiàn): "+count+" 次"); } } } 【程序50】??? 題目：有五個(gè)學(xué)生，每個(gè)學(xué)生有3門課的成績(jī)，從鍵盤輸入以上數(shù)據(jù)（包括學(xué)生號(hào)，姓名，三門課成績(jī)），計(jì)算出平均成績(jī)，把原有的數(shù)據(jù)和計(jì)算出的平均分?jǐn)?shù)存放在磁盤文件 "stud "中。 import java.io.*; import java.util.*; public class lianxi50 { public static void main(String[] args){ ?? Scanner ss = new Scanner(System.in); ?? String [][] a = new String[5][6]; ?? for(int i=1; i<6; i++) { ??? System.out.print("請(qǐng)輸入第"+i+"個(gè)學(xué)生的學(xué)號(hào)："); ??? a[i-1][0] = ss.nextLine(); ??? System.out.print("請(qǐng)輸入第"+i+"個(gè)學(xué)生的姓名："); ??? a[i-1][1] = ss.nextLine(); ??? for(int j=1; j<4; j++) { ?????? System.out.print("請(qǐng)輸入該學(xué)生的第"+j+"個(gè)成績(jī)："); ?????? a[i-1][j+1] = ss.nextLine(); ?????? } System.out.println("\n"); ?? } //以下計(jì)算平均分 float avg; int sum; for(int i=0; i<5; i++) { sum=0; ?? for(int j=2; j<5; j++) { ?? sum=sum+ Integer.parseInt(a[i][j]); ????? } ?? avg= (float)sum/3; ?? a[i][5]=String.valueOf(avg); } //以下寫磁盤文件 String s1; try { ??? File f = new File("C:\\stud"); ??? if(f.exists()){ ????? System.out.println("文件存在"); ????? }else{ ???????? System.out.println("文件不存在，正在創(chuàng)建文件"); ????????? f.createNewFile();//不存在則創(chuàng)建 ??????? } BufferedWriter output = new BufferedWriter(new FileWriter(f)); for(int i=0; i<5; i++) { for(int j=0; j<6; j++) { ?? s1=a[i][j]+"\r\n"; ?? output.write(s1);??? ??? } } output.close(); System.out.println("數(shù)據(jù)已寫入c盤文件stud中！"); ?? } catch (Exception e) { ???? e.printStackTrace(); ???? } } }
自己寫的程序：
1、?判斷一個(gè)數(shù)是否為素?cái)?shù)
public?class?lianxi33 {
public?static?void?main(String[] args) {
for?(int?i = 1; i <=10000; i++) {
int?n = i;
if?(isPrime(n)) {
System.out.println(i + "是素?cái)?shù)");
}
?
}
?
}
?
// 輸入一個(gè)數(shù)判斷其是否為素?cái)?shù)
public?static?boolean?isPrime(int?n) {
if?(n <= 1) {
return?false;
}
if?(n == 2) {
return?true;
}
if?(n % 2 == 0) {
return?false;
}
for?(int?i = 3; i <= (int) (Math.floor(Math.sqrt(n))) + 1; i = i + 2) {
if?(n % i == 0) {
return?false;
}
}
return?true;
}
?
}
?
2、二分法查找
public?class?BinarySearch {
?
public?static?int?binarySearch(int[] a, int?x) {
// 在a[0]<=a[1]<=...<=a[n-1]中搜索x
// 找到x則返回x的所在位置，否則返回-1
int?left = 0;
int?right = a.length?- 1;
?
while?(left <= right) {
int?middle = (left + right) / 2;
if?(x == a[middle])
return?middle;
if?(x > a[middle])
left = middle + 1;
else
right = middle - 1;
}
return?-1;
}
?
public?static?void?main(String[] args) {
int[] a = { 0, 1, 3, 6, 7, 10, 21, 34, 36, 40, 76 };
int?x = 34;// 設(shè)定要查找的數(shù)
int?position = binarySearch(a, x);
System.out.println(x + "在數(shù)組中的位置是"?+ position);
?
}
}
?
2、?比較器 二分查找
???import?java.util.TreeSet;
import?java.util.Iterator;
?
public?class?Student implements?Comparable<Student> {
????????private?int?id;
????????private?String name;
????????private?String dengji;
?
????????public?Student (int?id, String name, String dengji) {
????????????????this.id?= id;
????????????????this.name?= name;
????????????????this.dengji=dengji;
????????}
?
????????public?void?setId (int?id) {
????????????????this.id?= id;
????????}
?
????????public?void?setName (String name) {
????????????????this.name?= name;
????????}
????????public?void?setDengji (String dengji) {
????????????this.dengji?= dengji;
????}
?
????????public?int?getId () {
????????????????return?id;
????????}
?
????????public?String getName () {
????????????????return?name;
????????}
????????public?String getdengji () {
????????????return?dengji;
????}
?
????????/* Student 類的字符串表達(dá)式，形如：
?????????* 2 ??張三 */
?
????????public?String toString () {
????????????????return?(id?+ "\t"?+ name+"\t"?+ dengji);
????????}
?
????????/* 實(shí)現(xiàn) Comparable 接口中的 compareTo 方法，
?????????* 通常大于時(shí)返回一個(gè)正數(shù)，小于時(shí)返回一個(gè)負(fù)數(shù)，
?????????* 等于時(shí)返回零，具體情況可以自行決定。
?????????*********************************************************
?????????* 這里我根據(jù) id 號(hào)的大小進(jìn)行了比較。由于 TreeSet
?????????* 會(huì)根據(jù) compareTo 的結(jié)果來(lái)排序，因此輸出結(jié)果
?????????* 應(yīng)該是按照 id 號(hào)從小到大排序的。
?????????* 如果要根據(jù)姓名進(jìn)行排序，只需對(duì)這個(gè)方法進(jìn)行相應(yīng)的修改。*/
?
????????public?int?compareTo (Student arg) {
????????????????if?(id?> arg.id)
????????????????????????return?1;
????????????????else?if?(id?== arg.id)
????????????????????????return?0;
????????????????else
????????????????????????return?-1;
????????}
?
????????/* 以下為主方法，輸出結(jié)果是：
?????????* 3 ????John
?????????* 5 ????Tom
?????????* 7 ????Alice
?????????* 9 ????David
?????????* 可以看到不同于輸入順序，
?????????* TreeSet 已經(jīng)將其排序了。*/
?
????????public?static?void?main (String args[]) {
????????????????TreeSet<Student> tset = new?TreeSet<Student>();
????????????????tset.add(new?Student(5, "Tom"?, ?"a"));
????????????????tset.add(new?Student(3, "John", ?"b"?));
????????????????tset.add(new?Student(9, "David", ?"c"?));
????????????????tset.add(new?Student(7, "Alice"?, "d"));
?
????????????????Iterator<Student> itor = tset.iterator();
????????????????while?(itor.hasNext()) {
????????????????????????System.out.println(itor.next().toString());
????????????????}
????????}
}
?
**************************************************************************************************************************************************************
BinarySearch
import?java.util.Comparator;
?
public?class?BinarySearch?{
public?static?<T extends?Comparable<T>> int?binarySearch(T[] a, T x,
Comparator<T> comparator) {
if?(a == null) {
throw?new?IllegalArgumentException("被查找數(shù)組為null！");
} else?if?(x == null) {
throw?new?IllegalArgumentException("被查詢?cè)貫?/span>null！");
}
?
int?left = 0;
int?right = a.length?- 1;
?
while?(left <= right) {
int?middle = (left + right) / 2;
if?(comparator != null) {
if?(comparator.compare(x, a[middle]) == 0)
return?middle;
if?(comparator.compare(x, a[middle]) > 0)
left = middle + 1;
else
right = middle - 1;
}
?
??else?{ if(x.compareTo(a[middle])==0)
??return?middle;
??if(x.compareTo(a[middle])>0)
??left = middle + 1;
??else?right = middle - 1; }
?
}
return?-1;
}
?
public?static?void?main(String[] args) {
Student[] a = new?Student[4];
a[0] = (new?Student(3, "Tom"));
a[1] = (new?Student(5, "John"));
a[2] = (new?Student(7, "David"));
a[3] = (new?Student(9, "Alice"));
?
Student x = new?Student(7, "John");// 設(shè)定要查找的數(shù)
?
int?position = binarySearch(a, x, new?StudentComparator());
System.out.println(x + "在數(shù)組中的位置是"?+ position);
?
}
}
?
Student
import java.util.TreeSet;
import java.util.Iterator;
?
public class Student implements Comparable<Student> {
???????private int id;
???????private String name;
???????
?
???????public Student (int id, String name) {
???????????????this.id = id;
???????????????this.name = name;
???????????????
???????}
?
???????public void setId (int id) {
???????????????this.id = id;
???????}
?
???????public void setName (String name) {
???????????????this.name = name;
???????}
???????
?
???????public int getId () {
???????????????return id;
???????}
?
???????public String getName () {
???????????????return name;
???????}
???????
?
???????/* Student 類的字符串表達(dá)式，形如：
????????* 2 ??張三 */
?
???????public String toString () {
???????????????return (id + "\t" + name+"\t" );
???????}
?
???????/* 實(shí)現(xiàn) Comparable 接口中的 compareTo 方法，
????????* 通常大于時(shí)返回一個(gè)正數(shù)，小于時(shí)返回一個(gè)負(fù)數(shù)，
????????* 等于時(shí)返回零，具體情況可以自行決定。
????????*********************************************************
????????* 這里我根據(jù) id 號(hào)的大小進(jìn)行了比較。由于 TreeSet
????????* 會(huì)根據(jù) compareTo 的結(jié)果來(lái)排序，因此輸出結(jié)果
????????* 應(yīng)該是按照 id 號(hào)從小到大排序的。
????????* 如果要根據(jù)姓名進(jìn)行排序，只需對(duì)這個(gè)方法進(jìn)行相應(yīng)的修改。*/
?
???????public int compareTo (Student arg) {
???????????????if (id > arg.id)
???????????????????????return 1;
???????????????else if (id == arg.id)
???????????????????????return 0;
???????????????else
???????????????????????return -1;
???????}
?
???????/* 以下為主方法，輸出結(jié)果是：
????????* 3 ????John
????????* 5 ????Tom
????????* 7 ????Alice
????????* 9 ????David
????????* 可以看到不同于輸入順序，
????????* TreeSet 已經(jīng)將其排序了。*/
?
???????public static void main (String args[]) {
???????????TreeSet<Student> tset = new TreeSet<Student>();
???????????tset.add(new Student(5, "Tom" ));
???????????tset.add(new Student(3, "John"));
???????????tset.add(new Student(9, "David"));
???????????tset.add(new Student(7, "Alice"));
?
???????????Iterator<Student> itor = tset.iterator();
???????????while (itor.hasNext()) {
???????????????????System.out.println(itor.next().toString());
???????????}
???}
}
StudentComparator
import?java.util.Comparator;
?
/**
?* Student 比較器
?*/
public?class?StudentComparator?implements?Comparator<Student>
{
@Override
public?int?compare(Student s1, Student s2)
{
if(s1.getId()>s2.getId())
return?1;
else?if(s1.getId()==s2.getId())
return?0;
else
return?-1;
}
}
package test1;? ? /** ?* Title: Hello Java World ?* Description: 簡(jiǎn)單的Java程序,只顯示一個(gè)信息。 ?* filename: HelloWorld.java ?*/? ?public class HelloWorld {? ? public static void main(String[] args) {? ??? System.out.println("Hello Java World!");? ? }? ?}?
package test2;? /** ?* Title: Java語(yǔ)言流程演示 ?* Description: 演示Java中幾種常用的流程控制操作 ?* Filename: flowDome.java ?*/? ?public class flowDemo{? ?? public static void main(String[] arges){? ???? int iPara1,iPara2,iEnd;? ???? if(arges.length!=3)? ???? {? ?????? System.out.println("USE :java flowDome parameter1 parameter2 circle");? ?????? System.out.println("parameter1 : 比較條件1，數(shù)字類型");? ?????? System.out.println("parameter2 : 比較條件2，數(shù)字類型");? ?????? System.out.println("circle ：循環(huán)次數(shù)");? ?????? System.out.println("ego:java flowDome 1 2 5");? ?????? return;? ???? }else{? ?????? iPara1 = Integer.parseInt(arges[0]);? ?????? iPara2 = Integer.parseInt(arges[1]);? ?????? iEnd = Integer.parseInt(arges[2]);? ???? }? ???? //if語(yǔ)句? ???? if(iPara2>iPara1)? ???? {? ????? System.out.println("if 條件滿足！");? ????? System.out.println("第2個(gè)數(shù)比第1個(gè)數(shù)大！");? ???? }? ???? else? ???? {? ????? System.out.println("if 條件不滿足！");? ????? System.out.println("第2個(gè)數(shù)比第1個(gè)數(shù)小！");? ???? }? ???? //for循環(huán)操作? ???? for(int i=0;i<iEnd;i++)? ???? {? ?????? System.out.println("這是for 第"+i+"次循環(huán)");? ???? }? ???? //while循環(huán)操作? ???? int i=0;? ???? while(i<iEnd)? ???? {? ????? System.out.println("這是while 第"+i+"次循環(huán)");? ????? i++;? ???? }? ???? //do-while循環(huán)操作? ???? int j=0;? ???? do? ???? {? ????? System.out.println("這是do-while 第"+j+"次循環(huán)");? ????? j++;? ???? }while(j<iEnd);? ?? }? ?}?
package test3;? ? /** ?* Title: 數(shù)組數(shù)據(jù)操作 ?* Description: 演示一維數(shù)組和多維數(shù)組的初始化和基本操作 ?* Filename: myArray.java ?*/? ?public class? myArray{? ?? //初始化數(shù)組變量? ?? char[] cNum = {'1','2','3','4','5','6','7','8','9','0'};? ?? char[] cStr = {'a','b','c','d','e','f','g','h',? ????????????????? 'i','j','k','l','m','n','o','p',? ????????????????? 'q','r','s','t','u','v','w','x','y','z'};? ?? int[] iMonth = {31,28,31,30,31,30,31,31,30,31,30,31};? ?? String[] sMail = {"@","."};? /** ?*<br>方法說(shuō)明：校驗(yàn)電子郵件 ?*<br>輸入?yún)?shù)：String sPara 被校驗(yàn)的電子郵件字符 ?*<br>返回類型：boolean 如果校驗(yàn)的格式符合電子郵件格式返回true；否則返回false ?*/???? ?? public boolean isMail(String sPara){? ??? for(int i=0;i<sMail.length;i++){? ????? if(sPara.indexOf(sMail[i])==-1)? ??????? return false;?????????? ??? }? ??? return true;? ?? }? /** ?*<br>方法說(shuō)明：判斷是否是數(shù)字 ?*<br>輸入?yún)?shù)：String sPara。 需要判斷的字符串 ?*<br>返回類型：boolean。如果都是數(shù)字類型，返回true；否則返回false ?*/???? ?? public boolean isNumber(String sPara){? ???? int iPLength = sPara.length();? ???? for(int i=0;i<iPLength;i++){? ????? char cTemp = sPara.charAt(i);? ????? boolean bTemp = false;? ????? for(int j=0;j<cNum.length;j++){? ??????? if(cTemp==cNum[j]){? ????????? bTemp = true;? ????????? break;? ??????? }? ????? }? ????? if(!bTemp) return false;?? ???? }? ??? return true;? ?? }? /** ?*<br>方法說(shuō)明：判斷是否都是英文字符 ?*<br>輸入?yún)?shù)：String sPara。要檢查的字符 ?*<br>返回類型：boolean。如果都是字符返回true；反之為false ?*/???? ?? public boolean isString(String sPara){? ???? int iPLength = sPara.length();? ???? for(int i=0;i<iPLength;i++){? ????? char cTemp = sPara.charAt(i);? ????? boolean bTemp = false;? ????? for(int j=0;j<cStr.length;j++){? ??????? if(cTemp==cStr[j]){? ????????? bTemp = true;? ????????? break;? ??????? }? ????? }? ????? if(!bTemp) return false;?? ???? }? ??? return true;? ?? }? /** ?*<br>方法說(shuō)明：判斷是否是閏年 ?*<br>輸入?yún)?shù)：int iPara。要判斷的年份 ?*<br>返回類型：boolean。如果是閏年返回true，否則返回false ?*/???? ?? public boolean chickDay(int iPara){? ???? return iPara%100==0&&iPara%4==0;? ?? }? /** ?*<br>方法說(shuō)明：檢查日期格式是否正確 ?*<br>輸入?yún)?shù)：String sPara。要檢查的日期字符 ?*<br>返回類型：int 0 日期格式正確，-1 月或這日不合要求， -2 年月日格式不正確? ?*/? ?? public int chickData(String sPara){
??? @SuppressWarnings("unused")? ??? boolean bTemp = false；? ??? //所輸入日期長(zhǎng)度不正確? ??? if(sPara.length()!=10) return -2;?
//獲取年? ??? String sYear = sPara.substring(0,4);?
//判斷年是否為數(shù)字? ??? if(!isNumber(sYear)) return -2;
//獲取月份? ??? String sMonth = sPara.substring(5,7);?2011 05 05 ??? //判斷月份是否為數(shù)字? ??? if(!isNumber(sMonth)) return -2;? ??? //獲取日? ??? String sDay = sPara.substring(8,10);? ??? //判斷日是否為數(shù)字? ??? if(!isNumber(sDay)) return -2;? ??? //將年、月、日轉(zhuǎn)換為數(shù)字?
??? int iYear = Integer.parseInt(sYear);? ??? int iMon = Integer.parseInt(sMonth);? ??? int iDay = Integer.parseInt(sDay);? ??? if(iMon>12) return -1;? ??? //閏年二月處理? ??? if(iMon==2&&chickDay(iYear)){? ????? if(iDay>29) return 2;? ??? }else{? ????? if(iDay>iMonth[iMon-1]) return -1;? ??? }? ??? return 0;? ?? }? /** ?*<br>方法說(shuō)明：主方法，測(cè)試用 ?*<br>輸入?yún)?shù)： ?*<br>返回類型： ?*/?? ?? public static void main(String[] arges){? ???? myArray mA = new myArray();? ???? //校驗(yàn)郵件地址? ???? boolean bMail = mA.isMail("tom@163.com");? ???? System.out.println("1 bMail is "+bMail);? ???? bMail = mA.isMail("tom@163com");? ???? System.out.println("2 bMail is "+bMail);? ???? //演示是否是數(shù)字? ???? boolean bIsNum = mA.isNumber("1234");? ???? System.out.println("1：bIsNum="+bIsNum);? ???? bIsNum = mA.isNumber("123r4");? ???? System.out.println("2：bIsNum="+bIsNum);? ???? //演示是否是英文字符? ???? boolean bIsStr = mA.isString("wer");? ???? System.out.println("1：bIsStr="+bIsStr);? ???? bIsStr = mA.isString("wer3");? ???? System.out.println("2：bIsStr="+bIsStr);? ???? //演示檢查日期? ???? int iIsTime = mA.chickData("2003-12-98");? ???? System.out.println("1：iIsTime="+iIsTime);? ???? iIsTime = mA.chickData("2003-111-08");? ???? System.out.println("2：iIsTime="+iIsTime);? ???? iIsTime = mA.chickData("2003-10-08");? ???? System.out.println("3：iIsTime="+iIsTime);? ???? iIsTime = mA.chickData("2000-02-30");? ???? System.out.println("4：iIsTime="+iIsTime);? ?? }? ?}?
package test4;? ? import java.util.*;? /** ?* Title: 矢量操作< ?* Description: 演示一個(gè)矢量（Vector）的基本操作 ?* Filename: operateVector.java ?*/? public class operateVector?? {? /* *<br>方法說(shuō)明：生成一個(gè)4*4的二維Vector，供使用。 *<br>輸入?yún)?shù)： *<br>輸出變量：Vector *<br>其它說(shuō)明： */? ??? public Vector<Object> buildVector(){? ?????? Vector<Object> vTemps = new Vector<Object>();? ?????? for(int i=0;i<4;i++){? ????????? Vector<Object> vTemp = new Vector<Object>();? ????????? for (int j=0;j<4;j++){? ??????????? vTemp.addElement("Vector("+i+")("+j+")");? ????????? }? ????????? vTemps.addElement(vTemp);? ?????? }? ?????? return vTemps;? ??? }? /* *<br>方法說(shuō)明：插入數(shù)據(jù) *<br>輸入?yún)?shù)：Vector vTemp 待插入的數(shù)據(jù)對(duì)象 *<br>輸入?yún)?shù)：int iTemp 插入數(shù)據(jù)的位置 *<br>輸入?yún)?shù)：Object oTemp 插入數(shù)據(jù)值 *<br>輸出變量：Vector 結(jié)果 *<br>其它說(shuō)明：如果插入位置超出實(shí)例實(shí)際的位置將返回null
*/? ??? public Vector<Object> insert(Vector<Object> vTemp,int iTemp,Object oTemp){? ??????? if(iTemp>vTemp.size()){? ??????????? print("數(shù)據(jù)超界!");? ??????????? return null;? ??????? }else{? ???????????? vTemp.insertElementAt(oTemp,iTemp);? ??????? }? ??????? return vTemp;? ??? }? /* *<br>方法說(shuō)明：移除數(shù)據(jù) *<br>輸入?yún)?shù)：Vector vTemp 待刪除矢量對(duì)象 *<br>輸入?yún)?shù)：int iTemp 刪除數(shù)據(jù)的位置 *<br>輸出變量：Vector *<br>其它說(shuō)明：如果刪除超界的數(shù)據(jù)，將返回null */? ??? public Vector<Object> delete(Vector<Object> vTemp,int iTemp){? ??????? if(iTemp>vTemp.size()){? ??????????? print("數(shù)據(jù)超界!");? ??????????? return null;? ??????? }else{? ???????????? vTemp.removeElementAt(iTemp);? ??????? }? ??????? return vTemp;? ??? }? /* *<br>方法說(shuō)明：修改數(shù)據(jù) *<br>輸入?yún)?shù)：Vector vTemp 待修改矢量對(duì)象 *<br>輸入?yún)?shù)：int iTemp 修改數(shù)據(jù)的位置 *<br>輸入?yún)?shù)：Object oTemp 修改數(shù)據(jù)值 *<br>輸出變量：Vector *<br>其它說(shuō)明：如果修改位置超界的數(shù)據(jù)，將返回null */? ??? public Vector<Object> updata(Vector<Object> vTemp,int iTemp,Object oTemp){? ??????? if(iTemp>vTemp.size()){? ??????????? print("數(shù)據(jù)超界!");? ??????????? return null;? ??????? }else{? ???????????? vTemp.setElementAt(oTemp,iTemp);? ??????? }? ??????? return vTemp;? ??? }? /* *<br>方法說(shuō)明：輸出信息 *<br>輸入?yún)?shù)：String sTemp 輸出信息名稱 *<br>輸入?yún)?shù)：Object oTemp 輸出信息值 *<br>返回變量：無(wú) */? ??? public void print(String sTemp,Vector<Object> oTemp){? ??????? System.out.println(sTemp+"數(shù)據(jù)：");? ??????? this.print(oTemp);? ??? }? /** ?*<br>方法說(shuō)明：打印輸出（過(guò)載） ?*<br>輸入?yún)?shù)：Object oPara 輸出的對(duì)象 ?*<br>返回類型：無(wú) ?*/? ??? public void print(Object oPara){? ??????? System.out.println(oPara);? ??? }? /** ?*<br>方法說(shuō)明：打印輸出（過(guò)載） ?*<br>輸入?yún)?shù)：Vector vPara 顯示輸出矢量對(duì)象 ?*<br>返回類型：無(wú) ?*/? ??? public void print(Vector<Object> vPara){? ?????? for(int i=0;i<vPara.size();i++){? ??????? System.out.println(vPara.elementAt(i));? ?????? }? ??? }? /** ?*<br>方法說(shuō)明：主方法，程序入口 ?*<br>輸入?yún)?shù)：String[] args ?*<br>返回類型：無(wú) ?*/? ??? public static void main(String[] args)?? ??? {? ??????? operateVector ov = new operateVector();? ??????? Vector<Object> vTemp = ov.buildVector();? ??????? ov.print("vTemp0",vTemp);? ??????? Vector<Object> vResult = ov.insert(vTemp,2,"添加的數(shù)據(jù)");? ??????? ov.print("vResult",vResult);? ??????? Vector<Object> vResultup = ov.updata(vResult,2,"修改的數(shù)據(jù)");? ??????? ov.print("vResultmp",vResultup);? ??????? Vector<Object> vResultnow = ov.delete(vResultup,2);? ??????? ov.print("vResultnow",vResultnow);? ??? }? }?
package test5;? ? import java.util.*;? /** ?* Title: 哈希表操作 ?* Description: 這是一個(gè)權(quán)限認(rèn)證的例子，使用了哈希表作為數(shù)據(jù)的存儲(chǔ) ?* Filename: RoleRight.java ?*/? ?public class RoleRight? ?{? ?private static Hashtable<String, String> rightList = new Hashtable<String, String>();? /** ?*<br>方法說(shuō)明：初始化數(shù)據(jù) ?*<br>輸入?yún)?shù)： ?*<br>返回類型： ?*/? ?public void init()? ?{? ??? String[] accRoleList = {"admin","satrap","manager","user","guest"};? ??? String[] rightCodeList = {"10001","10011","10021","20011","24011"};? ??? for(int i=0;i<accRoleList.length;i++)? ??? {? ????? rightList.put(accRoleList[i],rightCodeList[i]);? ??? }? ?}? /** ?*<br>方法說(shuō)明：獲取角色權(quán)限代碼 ?*<br>輸入?yún)?shù)：String accRole 角色名稱 ?*<br>返回類型：String 權(quán)限代碼 ?*/? ?public String getRight(String accRole)? ?{? ??? if(rightList.containsKey(accRole))? ????? return (String)rightList.get(accRole);? ??? else? ????? return null;? ?}? /** ?*<br>方法說(shuō)明：添加角色和代碼信息 ?*<br>輸入?yún)?shù)：String accRole 角色名稱 ?*<br>輸入?yún)?shù)：String rightCode 角色權(quán)限代碼? ?*<br>返回類型：void （無(wú)） ?*/? ?public void insert(String accRole,String rightCode)? ?{? ?? rightList.put(accRole,rightCode);? ?}? /** ?*<br>方法說(shuō)明：刪除角色權(quán)限 ?*<br>輸入?yún)?shù)：String accRole 角色名稱 ?*<br>返回類型：void（無(wú)） ?*/? ?public void delete(String accRole)? ?{? ?? if(rightList.containsKey(accRole))? ???? rightList.remove(accRole);? ?}? /** ?*<br>方法說(shuō)明：修改角色權(quán)限代碼 ?*<br>輸入?yún)?shù)：String accRole 角色名稱 ?*<br>輸入?yún)?shù)：String rightCode 角色權(quán)限代碼? ?*<br>返回類型：void（無(wú)） ?*/? ?public void update(String accRole,String rightCode)? ?{? ?? //this.delete(accRole);? ?? this.insert(accRole,rightCode);? ?}? /** ?*<br>方法說(shuō)明：打印哈希表中角色和代碼對(duì)應(yīng)表 ?*<br>輸入?yún)?shù)：無(wú) ?*<br>返回類型：無(wú) ?*/? ?public void print()? ?{? ??? Enumeration<String> RLKey = rightList.keys();? ??? while(RLKey.hasMoreElements())? ??? {? ??????? String accRole = RLKey.nextElement().toString();? ??????? print(accRole+"="+this.getRight(accRole));? ??? }? ?}? /** ?*<br>方法說(shuō)明：打印信息（過(guò)載） ?*<br>輸入?yún)?shù)：Object oPara 打印的信息內(nèi)容 ?*<br>返回類型：無(wú) ?*/? ?public void print(Object oPara)? ?{? ??? System.out.println(oPara);? ?}? /** ?*<br>方法說(shuō)明：主方法， ?*<br>輸入?yún)?shù)： ?*<br>返回類型： ?*/? ?public static void main(String[] args)? ?{? ??? RoleRight RR = new RoleRight();? ??? RR.init();? ??? RR.print();? ??? RR.print("___________________________");? ??? RR.insert("presider","10110");? ??? RR.print();? ??? RR.print("___________________________");? ??? RR.update("presider","10100");? ??? RR.print();? ??? RR.print("___________________________");? ??? RR.delete("presider");? ??? RR.print();? ?}?? ?}//end:)~?
package test6;? ? /** ?* Title: 樹參數(shù) ?* Description: 使用繼承類，柳樹就是樹 ?* Filename: osier.java ?*/? class tree? {? /** ?*<br>方法說(shuō)明：樹的樹根 ?*/? ? public void root()? ? {? ??? String sSite = "土壤中";? ??? String sFunction = "吸收養(yǎng)份";? ??? print("位置："+sSite);? ??? print("功能："+sFunction);? ? }? /** ?*方法說(shuō)明：樹的樹干 ?*/? ? public void bolo()? ? {? ??? String sSite = "地面";? ??? String sFunction = "傳遞養(yǎng)份";? ??? print("位置："+sSite);? ??? print("功能："+sFunction);? ? }? /** ?*方法說(shuō)明：樹的樹枝 ?*/? ? public void branch()? ? {? ??? String sSite = "樹干上";? ??? String sFunction = "傳遞養(yǎng)份";? ??? print("位置："+sSite);? ??? print("功能："+sFunction);? ? }? /** ?*方法說(shuō)明：樹的葉子 ?*/? ? public void leaf()? ? {? ??? String sSite = "樹梢";? ??? String sFunction = "光合作用";? ??? String sColor = "綠色";
??? print("位置："+sSite);? ??? print("功能："+sFunction);? ??? print("顏色："+sColor);? ? }? /** ?*方法說(shuō)明：顯示信息 ?*輸入?yún)?shù)：Object oPara 顯示的信息 ?*/? ? public void print(Object oPara)? ? {? ??? System.out.println(oPara);? ? }? /** ?*方法說(shuō)明：主方法： ?*/? ? public static void? main(String[] arges)? ? {? ??? tree t = new tree();? ??? t.print("描述一棵樹：");? ??? t.print("樹根：");? ??? t.root();? ??? t.print("樹干：");? ??? t.bolo();? ??? t.print("樹枝：");? ??? t.branch();? ??? t.print("樹葉：");? ??? t.leaf();? ? }? }? /** ?* Title: 柳樹參數(shù) ?* Description: 描述柳樹的參數(shù) ?*/? class osier extends tree? {? ?/** ?*方法說(shuō)明：過(guò)載樹的樹葉 ?*/? ? public void leaf()? ? {? ??? super.leaf();? ??? String sShape = "長(zhǎng)形";? ??? super.print("形狀："+sShape);? ? }? ? /** ?*方法說(shuō)明：擴(kuò)展樹的花 ?*/? ? public void flower()? ? {? ??? print("哈哈，柳樹沒(méi)有花！！");? ? }? /** ?*方法說(shuō)明：主方法 ?*/? ? public static void? main(String[] args)? ? {? ??? osier o = new osier();? ??? o.print("柳樹樹根：");? ??? o.root();? ??? o.print("柳樹樹干：");? ??? o.bolo();? ??? o.print("柳樹樹枝：");? ??? o.branch();? ??? o.print("柳樹樹葉：");? ??? o.leaf();? ??? o.print("柳樹花：");? ??? o.flower();? ? }? }?
package test7;? ? /** ?*? Title:? 接口和抽象函數(shù)? ?*? Description: 演示繼承抽象函數(shù)和實(shí)現(xiàn)接口? ?*? Filename: newPlay.java ?*/? ?? //接口?? interface player? {? ?int flag = 1;? ?void play();//播放? ?void pause();//暫停? ?void stop();//停止? }//end :)? ? //抽象類? abstract class playing? {? ?public void display(Object oPara)? ?{? ?? System.out.println(oPara);??? ?}? ?abstract void winRun();? }//end :)? ? //繼承了playing抽象類和實(shí)現(xiàn)類player接口? public class newPlay extends playing implements player? {? ? public void play()? ? {? ??? display("newPlay.play()");//這里只是演示，去掉了代碼。? ? }? ? public void pause()? ? {? ???? display("newPlay.pause()");//這里只是演示，去掉了代碼。? ? }? ? public void stop()? ? {? ??? display("newPlay.stop()");//這里只是演示，去掉了代碼。? ? }? ? void winRun()? ? {? ??? display("newPlay.winRun()");//這里只是演示，去掉了代碼。? ? }? ? public static void main(String[] args)? ? {? ??? newPlay p = new newPlay();? ??? p.play();? ??? p.pause();? ??? p.stop();? ??? p.winRun();? ? }? }//end :)?
package test8.com;? ? /** ?* Title: 標(biāo)識(shí)符 ?* Description: 演示標(biāo)識(shí)符對(duì)類的訪問(wèn)控制 ?* Filename: ?*/? public class classDemo1 {? ??? // 公有方法? ??? public void mechod1() {? ??????? System.out.println("這是一個(gè)公有的方法！任何類都可以訪問(wèn)。");? ??? }? ? ??? // 授保護(hù)的方法? ??? protected void mechod2() {? ??????? System.out.println("這是一個(gè)受到保護(hù)的方法！只有子類可以訪問(wèn)。");? ??? }? ? ??? // 私有的方法? ??? private void mechod3() {? ??????? System.out.println("這是一個(gè)私有的方法！只有類本身才可以訪問(wèn)。");? ??? }? ? ??? public static void main(String[] args) {? ??????? classDemo1 d = new classDemo1();? ??????? d.mechod1();? ??????? d.mechod2();? ??????? d.mechod3();? ??? }? }?
package test8.com;? /** ?* Title: 標(biāo)識(shí)符 ?* Description: 演示標(biāo)識(shí)符對(duì)類的訪問(wèn)控制 ?* Filename:? ?*/? public class classPlay? {? ? public static void main(String[] args){? ??? classDemo1 d = new classDemo1();? ??? d.mechod1();? ??? d.mechod2();? ??? //d.mechod3();? ? }? }?
package test8.net;? ? import test8.com.classDemo1;? /** ?* Title: 標(biāo)識(shí)符 ?* Description: 演示標(biāo)識(shí)符對(duì)類的訪問(wèn)控制 ?* Filename:? ?*/? public class classPlay? {? ? public static void main(String[] args){? ??? classDemo1 d = new classDemo1();? ??? d.mechod1();? ? //d.mechod2();? ? //d.mechod3();? ? }? }?
package test9;? ? /** ?* Title: 捕獲異常和實(shí)現(xiàn)自己的異常 ?* Description: 通過(guò)繼承Exception類來(lái)實(shí)現(xiàn)自己的異常類。并使用try－catch來(lái)捕獲這個(gè)異常。 ?* Filename: ?*/? class MyException extends Exception {? ??? private static final long serialVersionUID = 1L;? ? ??? public MyException() {? ??? }? ? ??? public MyException(String msg) {? ??????? super(msg);? ??? }? ? ??? public MyException(String msg, int x) {? ??????? super(msg);? ??????? i = x;? ??? }? ? ??? public int val() {? ??????? return i;? ??? }? ? ??? private int i;? }? ? public class DemoException {? ??? /** ???? *方法說(shuō)明：使用MyException類中默認(rèn)的構(gòu)造器 ???? */? ??? public static void a() throws MyException {? ??????? System.out.println("Throwing MyException from a()");? ??????? throw new MyException();? ??? }? ? ??? /** ???? *方法說(shuō)明：使用MyException類中帶信息的構(gòu)造器 ???? */? ??? public static void b() throws MyException {? ??????? System.out.println("Throwing MyException from b()");? ??????? throw new MyException("Originated in b()");? ??? }? ? ??? /** ???? *方法說(shuō)明：使用了MyException中有編碼的構(gòu)造器 ???? */? ??? public static void c() throws MyException {? ??????? System.out.println("Throwing MyException from c()");? ??????? throw new MyException("Originated in c()", 47);? ??? }? ? ??? public static void main(String[] args) {? ??????? try {? ??????????? a();? ??????? } catch (MyException e) {? ??????????? e.getMessage();? ??????? }? ??????? try {? ??????????? b();? ??????? } catch (MyException e) {? ??????????? e.toString();? ??????? }? ??????? try {? ??????????? c();? ??????? } catch (MyException e) {? ??????????? e.printStackTrace();? ??????????? System.out.println("error code: " + e.val());? ??????? }? ??? }? } // end :)?
package test10;? ? import javax.swing.*;? import java.awt.*;? ? /** ?* Title: 創(chuàng)建自己的窗體? ?* Description:? ?* Filename:mainFrame.java ?*/? public class mainFrame extends JFrame {? ? ??? private static final long serialVersionUID = 1L;? ? ??? /** ???? *方法說(shuō)明：構(gòu)造器，通過(guò)傳遞參數(shù)來(lái)完成窗體的繪制。? ???? *輸入?yún)?shù)：String sTitle 窗體標(biāo)題? ???? *輸入?yún)?shù)：int iWidth 窗體的寬度 ???? *輸入?yún)?shù)：int iHeight 窗體的高度 返回類型： ???? */? ??? public mainFrame(String sTitle, int iWidth, int iHeight) {? ??????? Dimension dim = Toolkit.getDefaultToolkit().getScreenSize();// 獲取屏幕尺寸? ??????? ImageIcon ii = new ImageIcon("middle.gif");? ??????? setTitle(sTitle);// 設(shè)置窗體標(biāo)題? ??????? setIconImage(ii.getImage());// 設(shè)置窗體的圖標(biāo)? ??????? setDefaultCloseOperation(JFrame.DISPOSE_ON_CLOSE);// 設(shè)置但關(guān)閉窗體時(shí)退出程序? ??????? setSize(iWidth, iHeight);// 設(shè)置窗體大小? ??????? int w = getSize().width;// 獲取窗體寬度? ??????? int h = getSize().height;// 獲取窗體高度? ??????? System.out.println("窗體寬：" + w + " 窗體高：" + h);? ??????? int x = (dim.width - w) / 2;? ??????? int y = (dim.height - h) / 2;? ??????? setLocation(x, y);// 將窗體移到屏幕中間? ??????? setVisible(true);// 顯示窗體? ??? }? ? ??? public static void main(String[] args) {? ??????? JFrame.setDefaultLookAndFeelDecorated(true);// 使用最新的SWING外觀? ??????? new mainFrame("main Frame Demo", 400, 300);? ??? }? }?
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轉(zhuǎn)載于:https://www.cnblogs.com/BuleSky001/p/7635293.html
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