C Program to show swap of two numbers without using third variable

#include

void main()

{

 int a,b;

 printf("enter 1st no.");

 scanf("%d",&a);

 printf("enter 2nd no.");

 scanf("%d",&b);

 a=a+b;

 b=a-b;

 a=a-b;

 printf("%d is 1st no. and %d is 2nd no.\n",a,b);

}

Output: