產生特定範圍內的隨機數

1 // Generate a random number in the half-closed interval
2 // [range_min, range_max). In other words,
3 // range_min <= random number < range_max
4 int get_rand(int range_min, int range_max)
5 {
6     return (int)((double)rand() / (RAND_MAX + 1) * (range_max - range_min)
7         + range_min);
8 }