随机生成特定数字

Question

I want to randomly generate numbers from 1 - 5 but the catch is it should not randomly generate its currentFloor . My problem is from case 2 until 4. In case 2, it should randomly generate numbers 1, 3, 4, and 5. Same logic applies to case 3 and case 4.

switch(currentFloor) {
            //generates number from 2-5
            case 1:
                int destination1 = rand1.nextInt(3) + 2;
                destElevator.add(destination1);
                System.out.println(destElevator);
                break;
            case 2:
            case 3:
            case 4:
            //generates number from 1-4
            case 5:
                int destination2 = rand1.nextInt(3) + 1;
                destElevator.add(destination2);
                System.out.println(destElevator);
                break;
        }

Answer 1

Generate a number between 1 and 4, if the number is >= to currentFloor increment it by 1. This will work for all cases so you can compute it before the switch statement.

Actually from your code, if you use this strategy you don't even need the switch statement.

int destination = rand1.nextInt(4) + 1;
if (destination >= currentFloor) {
    destination++;
}
destElevator.add(destination)
System.out.println(destElevator);

Answer 2

mya be it could work :-

public int generator(int currentFloor){
    int result = currentFloor;
    while(result == currentFloor){
        result = 1 + (int)(Math.random() * (5 - 1));
    }
    return result;
}