Identifying, if there's duplicated inputted integer in Java

Question

How am I going to identify the duplicated inputted integer like If I input 1 1 2 3 4, it will say number 1 is been duplicated

import java.util.*;

public class Haha {

    static Scanner console = new Scanner(System.in);

    public static void main(String[] args) {

        int[] items = new int[5];
        int sum;

        System.out.println("Enter five integers: ");
        sum = 0;

        for (int counter = 0; counter < items.length; counter++) {
            items[counter] = console.nextInt();
            sum = sum + items[counter];
        }

        System.out.println("The sum of the numbers = " + sum);
        System.out.print("The numbers in the reverse" + "order are: ");

        for (int counter = items.length - 1; counter >= 0; counter--) {
            System.out.print(items[counter] + " ");
        }

        System.out.println();
    }
}

Use a hashMap to store the inputted values, so you can see in the hashMap if the value is already entert. — Jens
– Jens, Commented Dec 12, 2014 at 7:20
@Tiny haha was really original (and useless) you should have convert it to Haha instead! — Eypros
– Eypros, Commented Dec 12, 2014 at 7:20

TheLostMind · Accepted Answer · 2014-12-12 07:20:49Z

5

All you need is a Set :)

    int[] arr = { 1, 1, 2, 3, 4,3 };
    Set<Integer> hs = new HashSet<Integer>();
    for (int i = 0; i < arr.length; i++) {
        boolean b = hs.add(arr[i]);  // add returns false if the value is already present in the set
        if (!b) {
            System.out.println("duplicate value is : " + arr[i]);
        }
    }

O/P :

duplicate value is : 1
duplicate value is : 3

answered Dec 12, 2014 at 7:20

TheLostMind

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1 Comment

Manoj Sharma Over a year ago

TheLostMind is correct. Instead using int array use power of collection framework which will let you more control over values.

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