字符串类

#define _CRT_SECURE_NO_WARNINGSss#include <iostream>using namespace std;class String{private:char* _ptr;public:String()//构造函数:_ptr(new char[1]){_ptr[0] = '\0';}String(char* str)//构造函数重载:_ptr(new char[strlen(str)+1]){strcpy(_ptr,str);}String(const String& s)//拷贝构造:_ptr(new char[strlen(s._ptr)+1]){strcpy(_ptr,s._ptr);}String& operator=(const String& s)//赋值操作符的重载{if (this != &s){_ptr = s._ptr;}return *this;}~String()//析构函数{if (_ptr != NULL){delete[] _ptr;_ptr = NULL;}}public:char* Getstr(){return _ptr;}char& operator[](size_t index){return _ptr[index];}};int main(){String s1;cout<<"s1:"<<s1.Getstr()<<endl;String s2("abcd");cout << "s2:" << s2.Getstr() << endl;String s3(s2);cout << "s3:" << s3.Getstr() << endl;s1 = s3;cout << "s1:" << s1.Getstr() << endl;system("pause");return 0;}