How to generate a random int in C?

Question

Is there a function to generate a random int number in C? Or will I have to use a third party library?

Answer 1

STL doesn't exist for C. You have to call rand, or better yet, random. These are declared in the standard library header stdlib.h. rand is POSIX, random is a BSD spec function.

The difference between rand and random is that random returns a much more usable 32-bit random number, and rand typically returns a 16-bit number. The BSD manpages show that the lower bits of rand are cyclic and predictable, so rand is potentially useless for small numbers.