简单的计算器程序 c++

#include  <iostream>
using namespace std;
int add(int x,int y)
{
return x+y;
}
int minus(int x,int y)
{
return x-y;
}
int multi(int x,int y)
{
return x*y;
}
int divide(int x, int y)
{
return x/y;
}
void comput(int x,int y,int(*fp)(int,int))
{
cout<<(*fp)(x,y)<<endl;
}
int main ()
{
int x,y;
char a;
while (cin>>x>>a>>y &&(x||y))
{
switch (a)
{
case '+':
cout<<x<<a<<y<<"=";
comput(x,y,add);
break;
case '-':
cout<<x<<a<<y<<"=";
comput(x,y,minus);
break;
case '*':
cout<<x<<a<<y<<"=";
comput(x,y,multi);
break;
case '/':
cout<<x<<a<<y<<"=";
comput(x,y,divide);
break;
default:
break;
}
}
return 0;

}