Bug in random numbers in Android

Question

TreeSet myNumbers = new TreeSet();
Random randGen = new Random();

for (int i = 1; i <= 16; i++) {
    // number generation here
    int randNum = randGen.nextInt(16          


        

Answer 1

You're only generating one number in the range 1-15. You're then generating subsequent numbers with just nextInt:

if (myNumbers.add(randNum))
    break;
else
    randNum = randGen.nextInt();

That should be:

if (myNumbers.add(randNum))
    break;
else
    randNum = randGen.nextInt(16) + 1;

... and fix the initial call to nextInt to remove the "-1". (You don't need the 16 - 1, as explained in Josh's answer.)