将函数调用运算符“()”进行重载：
#include<iostream>
using namespace std;
class Add
{
public:
double operator ()(double a,double b);
};
double Add::operator() (double a,double b)
{
return a+b;
}
int main()
{
Add f;
cout<<f(2.5,3.2)<<endl;
return 0;
}原文：http://blog.csdn.net/qsyzb/article/details/18400905