Counting numbers up and down using Recursion

Question

Given two numbers, let\'s say start = 1 and end = 4, I am trying to count all the numbers in sequence up and then down . No looping is allowed

Answer 1

try this

 private static int  CountUpAndDown(int end, int first, int start)
    {
        if(end==first)
        {
            return -1;
        }
        if (start > end)
        {
           System.out.println(--end);
        }
        else {
            System.out.println(start++);
        }
        return CountUpAndDown(end, first, start);
    }

Answer 2

You just have to use the recursion for counting up. Then, when the function returns, you are on your way down. This can be achieved with:

public void countUpAndDown(int start, int end) {
    System.out.println(start);
    if (end == start) return;
    countUpAndDown(start+1, end);
    System.out.println(start);
}

Answer 3

You might be able to set it to a count up from 1->3 and >=4 do a -- down to 1.