88.++ --的重载

• shortsafe operator ++() 先自增再引用
• shortsafe operator ++(int) 先引用再自增后面,需要副本(先用副本进行操作,然后再进行自己类的++改变数据)(返回的都是修改后的数据)
• ()可以把对象名当做括号来操作

代码示例

#define _CRT_SECURE_NO_WARNINGS
#include <iostream>
using namespace std;

//shortsafe operator ++() 先自增再引用
//shortsafe operator ++(int) 先引用再自增后面,需要副本
//()可以把对象名当做括号来操作

class shortsafe
{
public:
    unsigned short sh = 0;
public:
    //没有参数++或者--在前面(先自增再引用)
    shortsafe operator ++()
    {
        
        if (this->sh < 65535)
        {
            this->sh++;
        }
        else
        {
            abort();
        }
        return *this;
    }

    //后加(先引用再自增)
    shortsafe operator ++(int)
    {
        //先引用副本
        shortsafe tmp;
        tmp.sh = this->sh;
        if (this->sh < 65535)
        {
            this->sh++;
        }
        else
        {
            abort();
        }
        return tmp;
    }

    //前减(先自减再引用)
    void operator --()
    {
        if (this->sh >0)
        {
            this->sh++;
        }
        else
        {
            abort();
        }
    }

    unsigned short operator()()
    {
        return this->sh;
    }

    shortsafe operator +(unsigned int num)
    {
        shortsafe tmp;
        if (tmp.sh + num <= 65535)
        {
            tmp.sh += num;
        }
        else
        {
            abort();
        }
    }
};


void main()
{
    shortsafe shsafe;
    shsafe.sh = 0;
    //重载不改变运算的优先级
    ++shsafe;
    cout << shsafe.sh << endl;
    cout << shsafe() << endl;
    cin.get();
}