函数指针的简单用法

#include <iostream>

using namespace std;

typedef double(*pFunc)(double &,double &);

double set_value(double &x,double &y)

{
cout<<"input height:";
cin>>x;
cout<<"input length:";
cin>>y;
return 0;

}

double t_area(double &x,double &y)

{
cout<<0.5*x*y<<endl;
return 0.5*x*y;

}

double s_area(double &x,double &y)

{
cout<<x*y<<endl;
return x*y;

}

double area(double &x,double &y,pFunc pf)

{
return pf(x,y);

}

int main()

{
double x,y;
//pFunc pf = NULL;
area(x,y,set_value);
area(x,y,t_area);
area(x,y,s_area);
return 1;

}