Question

Assignment #9 will be the construction of a program that reads in a sequence of integers from standard input until 0 is read, and store them in an array (including 0). This is done using iteration (choose one of for, while, or do while loop). You may assume that there will not be more than 100 numbers.

Then compute the minimum number, compute the largest number among the numbers that are divisible by 2, count even numbers, and compute the sum at indexes divisible by 3 (0, 3, 6, ...) using recursion. Thus you will create recursive methods findMin,computeMaxDivisibleBy2, countEvenNumbers, and computeSumOfNumbersAtIndexDivisibleBy3 in Assignment9 class and they will be called by a main method.

Specifically, the following recursive methods must be implemented (These methods should not contain any loop):

    public static int findMin(int[] numbers, int startIndex, int endIndex)

    public static int computeMaxDivisibleBy2(int[] elements, int startIndex, int endIndex)

    public static int countEvenNumbers(int[] elements, int startIndex, int endIndex)

    public static int computeSumOfNumbersAtIndexDivisibleBy3(int[] elements, int startIndex, int endIndex)

If these methods are implemented using a Loop or any Static Variable, points will be deducted (from the test cases) even if your program passes test cases. DO NOT use any Static Variables.

The program should output the results of those calculations to standard output. Your program will continue to read in numbers until the number 0 is entered. At this point, the calculations will be outputted in the following format:

The minimum number is 0

The largest integer that is divisible by 2 is 0

The count of even numbers in the sequence is 0

The sum of numbers at indexes divisible by 3 is 0

Note that the result values will be different depending on test cases (not always 0).

Do not output a prompt to query for the numbers. The number 0 is included in the sequence of numbers and should be included in all of your calculations.

Answer 1

Java Program

public class RecursionDemo { /** * Recursive method to find the Minimum value of an array using recursion * @param numbers * @param startIndex * @param endIndex * @return */ public static int findMin(int[] numbers, int startIndex, int endIndex) { if(startIndex == endIndex) return numbers[startIndex]; else return Math.min(numbers[startIndex], findMin(numbers, startIndex + 1, endIndex)); } /** * Recursive method to find the maximum number divisible by 2 * @param elements * @param startIndex * @param endIndex * @return */ public static int computeMaxDivisibleBy2(int[] elements, int startIndex, int endIndex) { if(startIndex == endIndex) return elements[startIndex]; else { if(elements[startIndex] % 2 == 0) { return Math.max(elements[startIndex], computeMaxDivisibleBy2(elements, startIndex + 1, endIndex)); } else { return computeMaxDivisibleBy2(elements, startIndex + 1, endIndex); } } } /** * Recursive method to count even numbers within an array * @param elements * @param startIndex * @param endIndex * @return */ public static int countEvenNumbers(int[] elements, int startIndex, int endIndex) { if(startIndex == endIndex && elements[startIndex] % 2 == 0) return 1; else if(startIndex == endIndex) return 0; int count; if(elements[startIndex] % 2 == 0) count = 1; else count = 0; return count + countEvenNumbers(elements, startIndex + 1, endIndex); } /** * Recursive methods to find the sum of numbers at index divisible by 3 * @param elements * @param startIndex * @param endIndex * @return */ public static int computeSumOfNumbersAtIndexDivisibleBy3(int[] elements, int startIndex, int endIndex) { if(startIndex >= endIndex) { if(startIndex == endIndex && startIndex % 3 == 0) { return elements[startIndex]; } else return 0; } else { if(startIndex % 3 == 0) { return elements[startIndex] + computeSumOfNumbersAtIndexDivisibleBy3(elements, startIndex + 3, endIndex); } else { return computeSumOfNumbersAtIndexDivisibleBy3(elements, startIndex + 3, endIndex); } } } public static void main(String args[]) { int arr[] = {2, 8, 10, 4, 6, 11, 18, -1, 4}; // change the array values to test the methods int startIndex = 0; int endIndex = arr.length - 1; System.out.println("The minimum number is: " + findMin(arr, startIndex, endIndex)); System.out.println("The maximum number divisible by 2 is: " + computeMaxDivisibleBy2(arr, startIndex, endIndex)); System.out.println("The number of even numbers is: " + countEvenNumbers(arr, startIndex, endIndex)); System.out.println("Sum of even numbers at index divisible by 3 is: " + computeSumOfNumbersAtIndexDivisibleBy3(arr, startIndex, endIndex)); } }

OUTPUT

1.1, problems @Javadoc ® Declaration 貝Console X <terminated> RecursionDemo (1) [Java Application] C:\Program FilesVava\jre1.8.0_4 The minimum number is: -1 The maximum number divisible by 2 is: 18 The number of even numbers is: 7 Sum of even numbers at index divisible by 3 is: 24