c++ 函数指针使用实例

#include <iostream>
double add(double x , double y)
{
return x + y;
}
double sub(double x , double y)
{
return x - y;
}
double acc(double x , double y)
{
return x * y;
}
double calculate(double x , double y , double (*fun)(double ,double))
{
return (*fun)(x , y);
}
int main()
{
using namespace std;
double (*fun[3])(double , double) = {add , sub , acc};
const char (*guugle[3]) = {"sum" , "diff" , "accumlate"};
double a , b;
cout << "Enter pairs of numbers (q to quit):" << endl;
int i;
while(cin >> a >> b)
{
for(i = 0 ; i < 3 ; i++)
{
cout << guugle[i] << " = " << calculate(a , b , fun[i]) << endl;
}
}
return 0;
}