操作符重载案例之字符串重载-蒲公英云

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;
}