Swapping Two Variables without Temp Variable

main( )
{
int a,b;
a=a+b;
b=a-b;
a=a-b;
printf("%a=%d b=%d",a,b);
}

Or

main()
{
int a,b;
a^=b; // a=a^b;
b^=a; // b=b^a;
a^=b; // a=a^b;
}