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

You can use the discrete_distribution class from the random library.

#include 
#include 
#include 

int main()
{
    std::discrete_distribution<> dist({ 1.0, 4.0, 4.0, 4.0 });  
    std::mt19937 eng(std::time(0));
    for (int i=0; i<100; ++i)
        std::cout << dist(eng);
}

Demo: http://ideone.com/z8bq4

If you can't use C++11, these classes also exist in boost.