Swapping two variables without using a temporary variable using the + and -:
x = a; y = b; x = x + y / / x = a + b; y = x - y / / y = a + b-b = a; x = x - y / / x = a + b-a = b; y = b; x = a; Problems with this approach: 1) It can cause overflow in the operation (+) 2) It can cause underflow on operation (-) Swapping two variables without using variables Temporary using XOR: x = a; y = b; x = x ^ y; y = x ^ y / / y = (x xor y) xor y = x xor (y xor y) xor x = 0 = x x = x ^ y / / x = (x xor y) xor x = (x xor y) xor y xor x = (x xor x) = y xor y = 0 Note that we use some properties of XOR: 1) Associativity 2) Commutativity 3) X = X 0 XOR We have no problems neither underflow nor overflow! Wladimir Araujo Tavares *Federal University of Ceará * -- You received this message because you are subscribed to the Google Groups "Algorithm Geeks" group. To post to this group, send email to algogeeks@googlegroups.com. To unsubscribe from this group, send email to algogeeks+unsubscr...@googlegroups.com. For more options, visit this group at http://groups.google.com/group/algogeeks?hl=en.
