结构体的运算符重载

1、定义结构体

struct Currency
{
     int Dollar;
     int Cents;
}

2、重载IO输出操作，在结构体内部将输入操作的重载定义为友元函数重载

friend ostream &operator<<(ostream &out,Currency value);

在结构体外部进行具体定义

ostream& operator<<(ostream &out,Currency value)
{
     out<< "The dollar = " <<value.Dollar<< " and The Cents = " <<value.Cents<<endl;
     return out;
}

3、重载结构体的“=”操作符（在结构体内部）

Currency& operator=(Currency& value)
     {
         Dollar = value.Dollar;
         Cents = value.Cents;
         return * this ;
     }

4、重载结构体的“+”操作符（在结构体内部）

Currency& operator+(Currency& value)
     {
         Dollar += value.Dollar;
         Cents += value.Cents;
         return * this ;
     }

5、重载结构体的"-"操作符（在结构体内部）

Currency &operator-(Currency& value)
     {
         Dollar = Dollar - value.Dollar;
         Cents = Cents - value.Cents;
         return * this ;
     }

6、重载结构体的“*”操作符（在结构体内部）

Currency& operator*(Currency& value)
     {
         Dollar *= value.Dollar;
         Cents *= value.Cents;
         return * this ;
     }

7、定义函数模板格式的输出函数

template < typename T>
void DisplayValue(T value)
{
     cout<<value<<endl;
}

附上完整程序代码。。。

#include "stdafx.h"
#include <iostream>
using namespace std;
 
template < typename T>
void DisplayValue(T value)
{
     cout<<value<<endl;
}
 
struct Currency
{
     int Dollar;
     int Cents;
     
     Currency& operator=(Currency& value)
     {
         Dollar = value.Dollar;
         Cents = value.Cents;
         return * this ;
     }
     Currency& operator+(Currency& value)
     {
         Dollar += value.Dollar;
         Cents += value.Cents;
         return * this ;
     }
     Currency &operator-(Currency& value)
     {
         Dollar = Dollar - value.Dollar;
         Cents = Cents - value.Cents;
         return * this ;
     }
     Currency& operator*(Currency& value)
     {
         Dollar *= value.Dollar;
         Cents *= value.Cents;
         return * this ;
     }
     friend ostream &operator<<(ostream &out,Currency value);
};
 
ostream& operator<<(ostream &out,Currency value)
{
     out<< "The dollar = " <<value.Dollar<< " and The Cents = " <<value.Cents<<endl;
     return out;
}
int _tmain( int argc, _TCHAR* argv[])
{
 
     Currency c1;
     c1.Dollar = 10;
     c1.Cents = 5;
     DisplayValue(c1);
     Currency c2,c3;
     c2 = c1;
     c3= c1+c2;
     DisplayValue(c3);
     system ( "pause" );
     return 0;
}