string实现
#include<iostream>
using namespace std;class String{friend ostream& operator<< (ostream&,String&);
public:String(const char* str=NULL); //賦值構造兼默認構造函數(char)String(const String &other); //賦值構造函數(String)String& operator=(const String&other); //operator=String operator+(const String &other)const; //operator+bool operator==(const String&); //operator==char& operator[](unsigned int); //operator[]size_t size(){return strlen(m_data);};~String(void) {delete[] m_data;}
private:char *m_data;
};
inline String::String(const char* str)
{if (!str) m_data=0;else{m_data = new char[strlen(str)+1];strcpy(m_data,str);}
}
inline String::String(const String& other)
{if(!other.m_data) m_data=0;else{m_data=new char[strlen(other.m_data)+1];strcpy(m_data,other.m_data);}
}
inline String& String::operator=(const String& other)
{if (this!=&other){delete[] m_data;if(!other.m_data) m_data=0;else{m_data = new char[strlen(other.m_data)+1];strcpy(m_data,other.m_data);}}return *this;
}
inline String String::operator+(const String &other)const
{String newString;if(!other.m_data)newString = *this;else if(!m_data)newString = other;else{newString.m_data = new char[strlen(m_data)+strlen(other.m_data)+1];strcpy(newString.m_data,m_data);strcat(newString.m_data,other.m_data);}return newString;
}
inline bool String::operator==(const String &s)
{if ( strlen(s.m_data) != strlen(m_data) )return false;return strcmp(m_data,s.m_data)?false:true;
}
inline char& String::operator[](unsigned int e)
{if (e>=0&&e<=strlen(m_data))return m_data[e];
}
ostream& operator<<(ostream& os,String& str)
{os << str.m_data;return os;
}
void main()
{String str1="Hello!";String str2="Teacher!";String str3 = str1+str2;cout<<str3<<"\n"<<str3.size()<<endl;cin.ignore(100, '\n');cin.get();
}
總結
