using X-OR 
#define SWAP(x,y) x^=y^=x^=y

x = x ^ y --> x^=y -- (1)
y = y ^ x --> y^=x -- (2)
x = x ^ y --> x^=y -- (3)

(3) in (2) --> y^=x^=y -- (4)
(4) in (1) --> x^=y^=x^=y -- :-)

all togeather, he single line code

#define SWAP(x,y) x^=y^=x^=y