hi is the <<(left shift)signed or unsigned? i was doing some revision in javacaps and it said that the left shift is signed and in R&H it does not specify and i assumed it was signed.could it be considered unsigned because it inserts zeroes in new positions like the >>>(un-signed right shift)? pls tell me .............. khella smith

There is no difference between a signed and an unsigned left shift, that's why there is only one left shift operator. In 8-bit terms: take a low(ish), positive number to start with 64 << 1 = 01000000 << 1 = 10000000 = 128 So that's how normal unsigned left shifts work. Now consider an unsigned, large number: 192 << 1 = 11000000 << 1 = 10000000 = 384 % 256 = 128 (Overflow) It still worked, even though the result did no longer fit inside an 8-bit number. The same bit pattern in signed guise: -64 << 1 = 11000000 << 1 = 10000000 = -128 This is exactly the right result. So you can see that left-shift works by shifting in zeroes from the right, on both signed and unsigned numbers. HTH - Peter