@Swap2Var@

Write a sample code to swap two variables without using a temporary variable

void swap(int x, int y)
{
x -= y;
y += x; // y gets the original value of x
x = (y - x); // x gets the original value of y
}

Correct. And this is the only solution which works for all pairs of integers (+ve/-ve)

Well i don't completely agree with your statement. There are other solutions to the same problem which are capable of handling both +ive and -ve inputs.

Of Course there are many other ways. Can you share one example here ?

just curious... if i make a call to ur function using the below snippet what will be the output...

int x =5, y =6;
swap(x,y);
printf("%d %d", x,y);

XOR can be used to do the same...

x ^= y;
y ^= x;
x ^= y;

The output for your snippet will be
5,6
The swap wont work here because it is 'pass by value'
instead if we use
swap(*x,*y)- pass by reference
The swapping will work fine.

void swap(int x,int y)
{
x=x+y;
y=x-y;
x=x-y;
}