How do i rewrite this program so that it displays only the even numbers in reverse?

Question

My program displays 10 digits that the user enters in reverse, but I want it to display the even numbers in reverse only. I tried doing so by writing an if statemntnumbers[i]%2=0 but it did not work. This is my code:

  Scanner input = new Scanner (System.in);

        int[] numbers = new int[10];
        System.out.println("Enter "+numbers.length+" integer numbers: ");

        for (int i = 0; i < numbers.length; i++) {
            numbers[i] = input.nextInt();

        }
        System.out.println("\nThe reverse of entered even numbers:  ");


        for (int i = numbers.length-1; i >=0; i--) {
            System.out.print(numbers[i] + " ");
        } System.out.print("\n");    }

Please show us the code that had the `if` statement you wrote. All we know is that you wrote this, somewhere. — ajb, Dec 21 '16 at 06:25
use `==` instead of `=' in if condition. Please go through java syntax properly. This a pretty obvious mistake. — Bopsi, Dec 21 '16 at 06:40

score 2 · Answer 1 · answered Dec 21 '16 at 06:24

What you described attempting should have worked, i.e.:

for (int i = numbers.length-1; i >=0; i--) {
    if (numbers[i] % 2 == 0) {
        System.out.print(numbers[i] + " ");
    }
}

One explanation for what happened is that you literally did this if statement:

if (numbers[i]%2=0) { ... }

which would fail because you are making an assignment, not checking an equality.

JDC · Answer 2 · 2016-12-21T07:33:10.730

1

Java 8 Version using Streams

int[] numbers = new int[] {1, 2, 3, 4, 5, 6, 7, 8, 9, 10};
Arrays.stream(numbers)
      .boxed()
      .sorted(Collections.reverseOrder())
      .filter(i -> i % 2 == 0)
      .forEach(System.out::println);

Update:
Output on single line with whitespace in between:

int[] numbers = new int[] {1, 2, 3, 4, 5, 6, 7, 8, 9, 10};
String output = Arrays.stream(numbers)
                       .boxed()
                       .sorted(Collections.reverseOrder())
                       .filter(i -> i % 2 == 0)
                       .map(String::valueOf)
                       .collect(Collectors.joining(" "));
System.out.println(output);

edited Dec 21 '16 at 07:33

answered Dec 21 '16 at 06:29

JDC

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Nice, except that the OP's code put all the output numbers on one line. As long as you're showing us how to write cool code, why don't you throw in a `joining` collector? :) – ajb Dec 21 '16 at 06:47
1

Done as requested ;) – JDC Dec 21 '16 at 07:33

score 0 · Answer 3 · edited Dec 21 '16 at 07:29

0

Correct it by using statement

if (numbers[numbers.length - 1] % 2 == 0) {
    //.....
}

edited Dec 21 '16 at 07:29

Dovydas Šopa

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answered Dec 21 '16 at 06:32

Parvesh chauhan

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How do i rewrite this program so that it displays only the even numbers in reverse?

3 Answers3

Java 8 Version using Streams