Swap 2 numbers without using third variable

Input	Two numbers a and  b to be swapped 
Output	Numbers after swapping
complexity O(1).

Swap(a , b)
1. a=a+b;
2. b=a-b;
3. a=a-b;
4. print a and b

//Swap two numbers without using temporary variable and pointers 
//Input : Swapped numbers

#include< stdio.h>
#include< conio.h>
int main()
{
    int a,b;
    printf("Enter two numbers ");
    scanf("%d%d",&a,&b);
    a=a+b;
    b=a-b;
    a=a-b;
    printf("No(s) after swapping are %d %d",a,b);
}