You can do it using the following logic:

Let us assume the numbers to be x and y.

Code:
if(x/y)
    printf("x is greater");
else
    printf("y is greater");
Logic:
If you divide a smaller number by a greater number the result will be "zero".

case 1: x<y
(x/y) results "0", in turn makes the condition if(o) => if(false) and so the else part is executed.

case 2:x>y
(x/y) results some positive value, in turn makes the condition to if(true) and so if part is executed.