Perfect random function

/**
* Get a perfect random value
* @param Minimum value
* @param Maximum value
* @return Random value between a and b-1
*/
int random(int a, int b)
{
    int i = b-a;
    do {
        n = rand();
    } while(n >= RAND_MAX-(RAND_MAX%i));
    return n%i+a;
}