在這里感謝新浪博客的daylive的博文:
?Map是c++的一個標準容器,她提供了很好一對一的關系,在一些程序中建立一個map可以起到事半功倍的效果,總結了一些map基本簡單實用的操作!
1.?map最基本的構造函數;
???map<string , int >mapstring;?????????map<int ,string >mapint;
???map<sring, char>mapstring;?????????map< char ,string>mapchar;
???map<char ,int>mapchar;????????????map<int ,char >mapint;
2.?map添加數據;
???map<int ,string> maplive;??
???1.maplive.insert(pair<int,string>(102,"aclive"));
???2.maplive.insert(map<int,string>::value_type(321,"hai"));
???3, maplive[112]="April";//map中最簡單最常用的插入添加!
3,map中元素的查找:
???find()函數返回一個迭代器指向鍵值為key的元素,如果沒找到就返回指向map尾部的迭代器。????????
???map<int ,string >::iterator l_it;;?
???l_it=maplive.find(112);
???if(l_it==maplive.end())
????????????????cout<<"we do not find 112"<<endl;
???else cout<<"wo find 112"<<endl;
4,map中元素的刪除:
???如果刪除112;
???map<int ,string >::iterator l_it;;
???l_it=maplive.find(112);
???if(l_it==maplive.end())
????????cout<<"we do not find 112"<<endl;
???else??maplive.erase(l_it);??//delete 112;
5,map中 swap的用法:
??Map中的swap不是一個容器中的元素交換,而是兩個容器交換;
??For example:
??#include <map>
??#include <iostream>
??using namespace std;
??int main( )
??{
??????map <int, int> m1, m2, m3;
??????map <int, int>::iterator m1_Iter;
??????m1.insert ( pair <int, int>??( 1, 10 ) );
??????m1.insert ( pair <int, int>??( 2, 20 ) );
??????m1.insert ( pair <int, int>??( 3, 30 ) );
??????m2.insert ( pair <int, int>??( 10, 100 ) );
??????m2.insert ( pair <int, int>??( 20, 200 ) );
??????m3.insert ( pair <int, int>??( 30, 300 ) );
???cout << "The original map m1 is:";
???for ( m1_Iter = m1.begin( ); m1_Iter != m1.end( ); m1_Iter++ )
??????cout << " " << m1_Iter->second;
??????cout???<< "." << endl;
???// This is the member function version of swap
???//m2 is said to be the argument map; m1 the target map
???m1.swap( m2 );
???cout << "After swapping with m2, map m1 is:";
???for ( m1_Iter = m1.begin( ); m1_Iter != m1.end( ); m1_Iter++ )
??????cout << " " << m1_Iter -> second;
??????cout??<< "." << endl;
???cout << "After swapping with m2, map m2 is:";
???for ( m1_Iter = m2.begin( ); m1_Iter != m2.end( ); m1_Iter++ )
??????cout << " " << m1_Iter -> second;
??????cout??<< "." << endl;
???// This is the specialized template version of swap
???swap( m1, m3 );
???cout << "After swapping with m3, map m1 is:";
???for ( m1_Iter = m1.begin( ); m1_Iter != m1.end( ); m1_Iter++ )
??????cout << " " << m1_Iter -> second;
??????cout???<< "." << endl;
}
6.map的sort問題:
??Map中的元素是自動按key升序排序,所以不能對map用sort函數:
??For example:
??#include <map>
??#include <iostream>
??using namespace std;
?int main( )
?{
???map <int, int> m1;
???map <int, int>::iterator m1_Iter;
???m1.insert ( pair <int, int>??( 1, 20 ) );
???m1.insert ( pair <int, int>??( 4, 40 ) );
???m1.insert ( pair <int, int>??( 3, 60 ) );
???m1.insert ( pair <int, int>??( 2, 50 ) );
???m1.insert ( pair <int, int>??( 6, 40 ) );
???m1.insert ( pair <int, int>??( 7, 30 ) );
???cout << "The original map m1 is:"<<endl;
???for ( m1_Iter = m1.begin( ); m1_Iter != m1.end( ); m1_Iter++ )
??????cout <<??m1_Iter->first<<" "<<m1_Iter->second<<endl;
??
}
??The original map m1 is:
??1 20
??2 50
??3 60
??4 40
??6 40
??7 30
??請按任意鍵繼續. . .
7,???map的基本操作函數:
??????C++ Maps是一種關聯式容器,包含“關鍵字/值”對
??????begin()??????????返回指向map頭部的迭代器
??????clear()?????????刪除所有元素
??????count()??????????返回指定元素出現的次數
??????empty()??????????如果map為空則返回true
??????end()????????????返回指向map末尾的迭代器
??????equal_range()????返回特殊條目的迭代器對
??????erase()??????????刪除一個元素
??????find()???????????查找一個元素
??????get_allocator()??返回map的配置器
??????insert()?????????插入元素
??????key_comp()???????返回比較元素key的函數
??????lower_bound()????返回鍵值>=給定元素的第一個位置
??????max_size()???????返回可以容納的最大元素個數
??????rbegin()?????????返回一個指向map尾部的逆向迭代器
??????rend()???????????返回一個指向map頭部的逆向迭代器
??????size()???????????返回map中元素的個數
??????swap()????????????交換兩個map
??????upper_bound()?????返回鍵值>給定元素的第一個位置
??????value_comp()??????返回比較元素value的函數
總結
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