操作符重载案例之字符串重载

本次案例自定义一个字符串类（Mystring），然后重载该字符串类以后，就可以向使用string类一样使用Mystring类了；

Mystring.h文件：

#ifndef __MYSTRING_H
#define __MYSTRING_H
class Mystring{
	friend void print(Mystring & oop);
public:
	/*空串  “”*/
	Mystring();
	Mystring(char *str);
	Mystring(Mystring &oop);
	~Mystring();
	Mystring& operator=(Mystring &oop);
private:
	int str_len;
	char *str;
};
void print(Mystring & oop);

#endif

Mystring.cpp文件：

#define _CRT_SECURE_NO_WARNINGS
#include "Mystring.h"
#include <iostream>
#include <string.h>
Mystring::Mystring()
{
	str_len = 0;
	this->str = new char[this->str_len + 1];
	strcpy(this->str, "");
}
Mystring::Mystring(char *str)
{
	if (str == NULL)
	{
		str_len = 0;
		this->str = new char[this->str_len + 1];
		strcpy(this->str, "");
	}
	else
	{
		this->str_len = strlen(str);
		this->str = new char[str_len+1];
		strcpy(this->str,str);
	}
}
/*拷贝构造函数*/
Mystring::Mystring(Mystring & oop)
{
	this->str_len = oop.str_len;
	this->str = new char[str_len + 1];
	strcpy(this->str,oop.str);
}
/*析构函数*/
Mystring::~Mystring()
{
	if (this->str != NULL)
	{
		delete [] this->str;
		this->str = NULL;
		this->str_len = 0;
		std::cout << "析构函数生效" << std::endl;

	}
}

/*输出字符串信息*/
void print(Mystring & oop)
{
	std::cout << oop.str << std::endl;
}

/*等号操作符重载*/
Mystring & Mystring::operator=(Mystring &oop)
{
	this->str_len = oop.str_len;
	this->str = new char[str_len + 1];
	strcpy(this->str, oop.str);
	return *this;
}

main.cpp为测试内容：

#include <iostream>
#include "Mystring.h"
using namespace std;
int main()
{
	{
		Mystring oop1("baibai");
		Mystring oop2("nihao");
		Mystring oop3 = oop2;//调用构造函数实现
		print(oop3);
		oop2 = oop1;//“字符串复制操作，通过等号运算符重载实现”
		print(oop2);
	}
	
	system("pause");
	return 0;
}