函数指针

#include<iostream>
using namespace std;


double add(double x, double y);
double calculate(double x, double y, double(*pf)(double, double));
int main(void)
{
using namespace std;
int x, y;
x = y = 0;
cin >> x >> y;
double z = calculate(x, y, add);
cout << z << endl;
cin.get();
cin.get();
return 0;
}
double add(double x, double y)
{
return x + y;
}
double calculate(double x, double y, double(*pf)(double, double))
{
double z = (*pf)(x, y);
return (x + y)*z;
}