How to swap two numbers in C without a third variable using XOR operator

• XOR operator is a bitwise operation that returns 1 if the bits are different and 0 if they are the same
• It can be used to swap two numbers by toggling their bits without using a third variable
• For example, if a = 10 and b = 40, then their binary representations are: a = 1010 b = 101000
• Applying XOR operator to both numbers gives:
  a = a ^ b // a = 100010 b = a ^ b // b = 1010 a = a ^ b // a = 101000
• Converting back to decimal gives:
  a = 34 b = 10 a = 40
• Now, a and b have been swapped

Swapping Code:

#include<stdio.h>
int main()
{
int a = 10, b = 40;
printf("Before swap: a = %d ; b = %d\n", a, b);
a = a ^ b; // a = 34
b = a ^ b; // b = 10
a = a ^ b; // a = 40
printf("After swap: a = %d ; b = %d\n", a, b);
return 0;
}

Pros and cons of using XOR operator to swap two numbers in C

XOR operator is a bitwise operation that returns 1 if the bits are different and 0 if they are the same.

It can be used to swap two numbers by toggling their bits without using a third variable.

Here are some of the benefits and drawbacks of this technique:

Benefits

1. It saves memory and improves performance by avoiding a third variable.]
2. It works for both integers and floating-point numbers, unlike arithmetic operators like + and – or * and /.
3. It avoids overflow or underflow issues that may occur with arithmetic operators.

Drawbacks

1. It is not very easy to understand or follow, unlike arithmetic operators.
2. It may fail for some edge cases, such as when both numbers are zero or when both numbers are equal.
3. It may not be compatible with some compilers or platforms, unlike arithmetic operators.