Question

2. Write a function that takes an array of integers as an argument and returns a value based on the sums of the even and odd numbers in the array. Let X = the sum of the odd numbers in the array and let Y = the sum of the even numbers. The function should return X – Y

The signature of the function is:
int f(int[ ] a)

Examples

if input array is	return
{1}	1
{1, 2}	-1
{1, 2, 3}	2
{1, 2, 3, 4}	-2
{3, 3, 4, 4}	-2
{3, 2, 3, 4}	0
{4, 1, 2, 3}	-2
{1, 1}	2
{}	0

by java program

Answer 1

public class EvenOddSumDiff {

    public static int f(int[] a) {
        int X = 0, Y = 0;
        for (int i = 0; i < a.length; i++) {
            if (a[i] % 2 == 0) {
                Y += a[i];
            } else {
                X += a[i];
            }
        }
        return X - Y;
    }

    public static void main(String[] args) {
        System.out.println(f(new int[]{1}));
        System.out.println(f(new int[]{1, 2}));
        System.out.println(f(new int[]{1, 2, 3}));
        System.out.println(f(new int[]{1, 2, 3, 4}));
        System.out.println(f(new int[]{3, 3, 4, 4}));
        System.out.println(f(new int[]{3, 2, 3, 4}));
        System.out.println(f(new int[]{4, 1, 2, 3}));
        System.out.println(f(new int[]{1, 1}));
        System.out.println(f(new int[]{}));
    }
}