Answer to Question #155179 in C++ for zain ul abdeen

Question

 Write a program which takes two integers (num1 and num2) as input from the user.

Your program should display on the screen the result of i) num1 + num2, ii) num1 * num2, and iii) num1 - num2.

You are not allowed to use the + or - or * operators. E.g., cout<<num1+num1<<num1*num2<<num1-num2; is not allowed. += or -= or *= operators are also not allowed.

You HAVE TO USE loops and the ++ and -- operators. Code for num1+num2 is already available in the slides. Use that for this assignment.

Answer 1

Here is the code:

#include <iostream>

int sum(int a, int b)
{
   if (b < 0)
       for (int i = 0; i > b; i--) a--;
   else
       for (int i = 0; i < b; i++) a++;

   return a;
}

int diff(int a, int b)
{
   if (b < 0)
       for (int i = 0; i > b; i--) a++;
   else
       for (int i = 0; i < b; i++) a--;

   return a;
}

int mult(int a, int b)
{
   int ab = 0;

   if (b < 0)
       for (int i = 0; i > b; i--) ab = diff(ab, a);
   else
       for (int i = 0; i < b; i++) ab = sum(ab, a);

   return ab;
}

int main()
{
   int num1, num2;
   std::cin >> num1 >> num2;

   std::cout << num1 << " + " << num2 << " = " << sum(num1, num2) << std::endl;
   std::cout << num1 << " * " << num2 << " = " << mult(num1, num2) << std::endl;
   std::cout << num1 << " - " << num2 << " = " << diff(num1, num2) << std::endl;

   return 0;
}