Question

I seem to have a problem with declarations screwing up my math. Any advice or suggestions are highly welcomed.

Here’s the code:

int num1, num2, num3, num4, op, ;
    op = ((1==num3) || (2==num4)); 
    num3 = (num1 + num2);
    num4 = (num1 * num2);

I’ve been trying lots of arrangements and re-assignments. A lot has compiled, but when 5 + 5 = 2659043, there’s a problem…

Answer 1

Not sure what you’re trying to do, but this is what your code is doing:

int num1, num2, num3, num4, op, ;

This line informs the C compiler that it needs to allocate space for 5 integers (num1, num2, num3, num4, op), these integers can now be used as variables until the scope expires. Not sure why you have the last ‘,’ you might want to remove that.

op = ((1==num3) || (2==num4)); 

If num3 is 1, or num4 = 2, then set op to 1 (true). Otherwise, set op to 0 (false).

num3 = (num1 + num2);

Self-explanatory: Add num1 and num2 and put the sum into num3.

num4 = (num1 * num2);

Self explanatory: Multiply num1 and num2 and put the product into num4.

Immediately I see an issue with your program. You are using these variables, but have not initialized them to anything. For example, how is there supposed to be a sum of (num1 + num2) if num1 and num2 do not have a value. Try this:

#include <stdio.h>

int main()
{
   int num1, num2, sum;
   num1 = 1;
   num2 = 2;
   sum = num1 + num2;

   printf("sum = %d\n", sum);
}