Generate random numbers except certain values

Question

I want to generate random numbers, but don't want them to be from exclude array. Here is my code.

public int generateRandom(int start, int end, ArrayList<Integer> exclude) {
    Random rand = new Random();
    int range = end - start +1 - exclude.size();
    int random = rand.nextInt(range) + 1;

    for(int i = 0; i < exclude.size(); i++) {
        if(exclude.get(i) > random) {
            return random;
        }
      random++;
    }

    return random;
}

I use this function in a while loop, and during each iteration I add a new value to exclude. Sometimes it returns numbers that belong to exclude. What's the problem?

Answer 1

this worked for me:

    public int randomInt(int start, int end, int... exception) {
        int result = -1;
        Random rand = new Random();
        int range = end - start + 1;
        boolean equals = true;

        while(equals) {
            result = rand.nextInt(range);
            boolean differentOfAll = true;
            for(int i : exception) {
                if(result==i) {
                    differentOfAll = false;
                    break;
                }
            }
            if(differentOfAll) {
                equals = false;
            }
        }

        return result;
    }