changing probability of getting a random number

Question

I would like to generate a random number between 0 and 3 and I have the following in my code:

int random = rand() % 4;

This works fine but

Answer 1

I would just map more values to 1,2,3 from a larger set. For example: 9 and map 1,2,3 => 1, 3,4,5=>2, 6,7,8=>3 and 0 for zero. There are other ways, but I am working within your question