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11.8.1. Base Case Practice¶

A recursive method contains a call to itself. The recursion stops when a base case test is true and a value is returned.

10-7-1-1: Click on the line or lines that contain the test for the base caseWhen a base case test is true a value is returned and the recursion stops

public static int mystery(int n)
{
    if (n == 0)
    {
        return 1;
    }
    else
    {
        return 2 * mystery (n - 1);
    }
}

10-7-1-2: Click on the line or lines that contain the test for the base caseWhen a base case test is true a value is returned and the recursion stops

public static int bunnyEars(int bunnies)
{
    if (bunnies == 0)
    {
        return 0;
    }
    else if (bunnies == 1)
    {
        return 2;
    }
    else
    {
        return 2 + bunnyEars(bunnies - 1);
    }
}

10-7-1-3: Click on the line or lines that contain the test for the base caseWhen a base case test is true a value is returned and the recursion stops

public static void mystery (int x) {
    System.out.print(x % 10);
    if ((x / 10) != 0)
    {
        mystery(x / 10);
    }
    System.out.print(x % 10);
}

10-7-1-4: Click on the line or lines that contain the test for the base caseWhen a base case test is true a value is returned and the recursion stops

public static int mystery(String str)
{
    if (str.length() == 1)
    {
        return 0;
    }
    else
    {
        if (str.substring(0, 1).equals("y"))
        {
            return 1 + mystery (str.substring(1));
        }
        else
        {
            return mystery(str.substring(1));
        }
      }
   }