Java program to find the frequency of elements in an array

Frequency of elements in an array in java

Now we will learn the program to find Frequency of elements in an array in java which is discussed here. Given an array, the task is to find the frequency of all the elements of the array.For example, consider the following array

Input:

arr = {1, 2, 3, 5, 2,  7, 3, 5}

Output:

1 occurs 1 times

2 occurs 2 times

3 occurs 2 times

5 occurs 2 times

7 occurs 1 times

java program to find frequency of elements
Frequency of each element of an array

Algorithm

 

  • Input the number of elements of an array.
  • Input the array elements.
  • Create another array to store the frequency of elements.
  • Traverse the input array and update the count of the elements in the frequency array.
  • Print the frequency array which displays the frequency of all the elements of the array

 

import java.util.Arrays;


import java.util.Scanner;  


public class test {
    

    public static void main(String[] args) {
        
        Scanner input = new Scanner (System.in);
        int[] arr = new int[8];
         System.out.println("Elements are not of original array");
         for (int i = 0;i< arr.length; i++) {
                
                
//           calling the  nextInt for appending the element in the arrays
           arr[i]=input.nextInt();
               
       }
        
           
            //Array freq will store frequencies of element  
            int [] fr = new int [arr.length];  
            int visited = -1;  
            
            for(int i = 0; i < arr.length; i++){  
                int count = 1;  
                for(int j = i+1; j < arr.length; j++){  
                    if(arr[i] == arr[j]){  
                        count++;  
                        //To avoid counting same element again  
                        fr[j] = visited;  
                    }  
                }  
                if(fr[i] != visited)  
                    fr[i] = count;  
            }  
            
            //Displays the frequency of each element present in array  
            for(int i = 0; i < fr.length; i++){  
                if(fr[i] != visited)  
                    System.out.println(arr[i] + " occurs "+ fr[i]+" times ");  
            }  
        } 
    }
output
Elements are not of original array 1 2 3 1 2 4 5 5 1 occurs 2 times 2 occurs 2 times 3 occurs 1 times 4 occurs 1 times 5 occurs 2 times

output
Elements are not of original array 11 22 33 11 22 44 55 55 11 occurs 2 times 22 occurs 2 times 33 occurs 1 times 44 occurs 1 times 55 occurs 2 times

7 comments on “Java program to find the frequency of elements in an array”


    • HelpPrepInsta

      Hey Kandukuri, we don’t have this code in C, we’ll work on it asap, it’ll be really helpful if you can provide us with the code, and we’ll post your code on our page


      • Aditi

        public class Main
        {
        public static void main(String[] args)
        {
        int [] arr = new int [] {1, 2, 8, 3, 2, 2, 2, 5, 1, 5, 7, 3, 5, 9, 8};
        int [] fr = new int [arr.length];
        int visited = -1;
        for(int i = 0; i < arr.length; i++)
        {
        int count = 1;
        for(int j = i+1; j < arr.length; j++)
        {
        if(arr[i] == arr[j])
        {
        count++;
        fr[j] = visited;
        }
        }
        if(fr[i] != visited)
        fr[i] = count;
        }
        System.out.println("—————————————");
        System.out.println(" Element | Frequency");
        System.out.println("—————————————");
        for(int i = 0; i < fr.length; i++){
        if(fr[i] != visited)
        System.out.println(" " + arr[i] + " | " + fr[i]);
        }
        System.out.println("—————————————-");
        }
        }