Программа-прототип простого калькулятора для дробей,
только без сокращения результата :) .

//------------------------------------------------------------------------------------------------
#include <iostream>
#include <conio.h>
using namespace std;
int main()
{
int a, b, c, d;
char ch='a', operation='p', cool='o';
while(cool!='n') //Начало цикла while
{
cout<<"Enter the 1st drob: ";
cin>>a>>ch>>b;
cout<<"Enter the operation (+,-,*,/): ";
cin>>operation;
cout<<"Enter the 2nd drob: ";
cin>>c>>ch>>d;
switch(operation) // Ветвление switch
{
case '+':
cout<<(a*d+b*c)<<ch<<(b*d)<<endl;
break;
case '-':
cout<<(a*d-b*c)<<ch<<(b*d)<<endl;
break;
case '*':
cout<<(a*c)<<ch<<(b*d)<<endl;
break;
case '/':
cout<<(a*d)<<ch<<(b*c)<<endl;
break;
default:
cout<<"wrong operation, enter new.";
cout<<endl;
continue;
}
cout<<"Do you whant to continue? (y/n): ";
cool=getch();
}
return 0;
}

//------------------------------------------------------------------------------------------------