【C++】String类拷贝构造函数——深拷贝普通版和简洁版

#define  _CRT_SECURE_NO_WARNINGS 1#include<iostream>using namespace std;class String{public://构造函数String(char* pStr = ""){if (NULL == pStr){_pStr = new char[1];*_pStr = '\0';}else{_pStr = new char[strlen(pStr) + 1];strcpy(_pStr, pStr);}}////拷贝构造函数1 简洁版//String(const String& pStr)//:_pStr(NULL)//{//String temp(pStr._pStr);//swap(_pStr, temp._pStr);//}//拷贝构造函数2 普通版String(String& pStr):_pStr(new char[strlen(pStr._pStr)+1]){strcpy(_pStr, pStr._pStr);}////赋值运算符重载1//String& operator=(const String& pStr)//{//if (this != &pStr)//{//String temp(pStr._pStr);//swap(_pStr, temp._pStr);//}//return *this;//}//赋值运算符重载2String& operator=(const String& pStr){if (this != &pStr){//防止new开辟内存失败，丢失原来内存char* ptr = new char[strlen(pStr._pStr) + 1];strcpy(ptr, pStr._pStr);delete[]_pStr;_pStr = ptr;}return *this;}//析构函数~String(){if (NULL != this){delete[]_pStr;_pStr = NULL;}}friend ostream& operator<<(ostream& _cout, const String& pStr);private:char* _pStr;};ostream& operator<<(ostream& _cout, const String& pStr){_cout << pStr._pStr;return _cout;}void Funtest(){String s1("hehe");cout << s1 << endl;String s2;s2 = s1;cout << s2 << endl;String s3(s1);cout << s3 << endl;}void Funtest2(){String s1("hello");String s2(s1);cout << s1 << endl;cout << s2 << endl;cout << "##################" << endl;String s3("world");cout << s3 << endl;s3 = s1;cout << s3 << endl;cout << "##################" << endl;}int main(){Funtest2();system("pause");return 0;}