CODEWITHSUNDEEP
javarandom
chinloyal
chinloyal

Reputation: 1141

Generate random numbers with the first one being zero

I know how to get a range of random numbers between 0 zero and any number.

But what I want to know is, since the random number generator is not truly random, and follows a specific algorithm, for example if you pass a seed of 20. then it will always generate the same sequence of numbers: 17, 292, 0, 9.

So I get that. Since it follows a specific algorithm, is there a way I can force the generator to always start at zero or any other number?

But specifically zero in my case.

Upvotes: 3

Views: 2421

Answers (2)

Benoit
Benoit

Reputation: 5394

No need to hack the Random class, just write your own:

public class RandomGenerator {

    private int bound;
    private Random random;
    private boolean firstCall = true;

    public RandomGenerator(int bound, long seed) {
        this.bound = bound;
        random = new Random(seed)
    }

    public int next() {
        if (firstCall) {
            firstCall = false;
            return 0;
        }
        return random.nextInt(bound);
    }
}

Upvotes: 5

matt
matt

Reputation: 12347

public static void main (String[] args) throws java.lang.Exception
    {
        int x = -1;
        long seed = 0;
        int xxx = 100;
        while(x!=0){

            Random s = new Random(seed++);
            x = s.nextInt(xxx);

        }
        System.out.println("seed " + (seed-1) + " gives " + new Random(seed-1).nextInt(xxx));

    }

This will find a seed that the next int will be zero for a given modulus. (Happens to be 18 for this example).

Upvotes: 0

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