How to print the individual occurance of elements in Java

Question

I want to print the individual occurence of every element in array. How can i do it?

eg:

{1,1,1,2,2,2,2,3,3,3,3,3,1,1,1,2}

O/P : 1: 6 , 2: 5 , 3: 5

Thank you in advance.

Answer 1

You can use a HashMap to serve the purpose.

In the HashMap you can store the elements and the count of it.

Here is a simple implementation I used.

import java.util.HashMap;
import java.util.Scanner;
public class CountElement 
{
    public static void main(String[] args) 
    {
        Scanner scan = new Scanner(System.in);
        System.out.println("Enter the number of elements in the Array");
        int n = scan.nextInt();
        int arr[] = new int [n];
        System.out.println("Enter "+n+" elements");
        for(int i=0; i<n; i++)
        {
            arr[i] = scan.nextInt();
        }
        HashMap<Integer,Integer> countMap = new HashMap<Integer, Integer>();
        for (int i : arr)
        {
            if (countMap.containsKey(i))
            {
                countMap.put(i, countMap.get(i)+1);
            }
            else
            {
                countMap.put(i, 1);
            }
        }
        System.out.println(countMap);
    }
}

Output:

Enter the number of elements in the Array
7
Enter 7 elements
1 2 1 1 2 3 4 
{1=3, 2=2, 3=1, 4=1}

Hope this will suffice your work.