操作符重载案例之字符串重载

素颜马尾好姑娘i 2022-06-09 12:27 207阅读 0赞

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;
    }