C program in Nepali | Swap Two Numbers Without using third Variable

The Concept of Using + and - for Swapping
If there are two numbers. Suppose first number becomes total. Then if you subtract second number from total, you'll get the first number. Therefore it gets initialized to num2 (that now holds the initial value of num1). Again if you subtract the new value of second number (initial value of first number) from total, then you will get the initial value of second number. Therefore it gets initialized to num1 (that now holds the initial value of num2).