> Compute the sign of an integer > On the other hand, if you prefer the result be either -1, 0, or +1, then use: > sign = (v != 0) | -(int)((unsigned int)((i

> Compute the sign of an integer > On the other hand, if you prefer the result be either -1, 0, or +1, then use: > sign = (v != 0) | -(int)((unsigned int)((int)v) >> (sizeof(int) * CHAR_BIT - 1)); > // Or, for more speed but less portability: > sign = (v != 0) | (v >> (sizeof(int) * CHAR_BIT - 1)); // -1, 0, or +1 > // Or, for portability, brevity, and (perhaps) speed: > sign = (v > 0) - (v < 0); // -1, 0, or +1 Or if you prefer portability, speed, and readability at the same time: int sign(int i) { if(i > 0) return 1; else if(i < 0) return -1; else return 0; } gets compiled to mov ecx, edi sar ecx, 31 test edi, edi mov eax, 1 cmovle eax, ecx ret which is the bit shift hack. (still useful as a reference for implementing an optimizer, to be read as pseudo code)