仿函数

/*

         重载operator()

*/

#include<iostream>using namespace std;template<class T>struct Plus{    T operator()(const T &x,const T &y)const    {        return x+y;    }};template<class T>struct Minus{    T operator()(const T &x,const T &y)const    {        return x-y;    }};int main(void){    Plus<int> PlusInt;    Minus<int> MinusInt;    cout<<PlusInt(5,9)<<endl;    cout<<MinusInt(2,19)<<endl;    cout<<Plus<int>()(42,50)<<endl;    cout<<Minus<int>()(43,50)<<endl;    return 0;}