Question

I am looking for a way to generate a random integer from 0-x, where x is defined at runtime by the human user. However, half of those numbers must be greater than zero and less than or equal to 5 (0,5] and the other half must be in the set of [6,x].

I know that the following code will generate a number from 0-x. The main problem is ensuring that half of them will be in the set of (0,5]

    Math.random() * x;

I’m not looking for someone to do this for me, just looking for some hints. Thank you!

Answer 1

You could first flip a coin and based on that generate upper or lower number:

final Random rnd = new Random();
while (true)
  System.out.println(rnd.nextBoolean()? rnd.nextInt(6) : 6 + rnd.nextInt(x-5));

Or, using the unwieldy Math.random() (bound to have trouble at the edges of the range):

while (true)
  System.out.println(Math.floor(
     math.random() < 0.5 ? (Math.random() * 6) : (6 + (x-5) * Math.random())
  ));

Consider this as a hint only 🙂