Program to find the frequency of each element in an array

#include<stdio.h>
#define MAX_SIZE 100

int main()
{
    int arr[MAX_SIZE], freq[MAX_SIZE];
    int n, i, j, count;
    
    printf("Enter size of array: ");
    scanf("%d", &n);
    
    // Input elements in array
    printf("Enter elements in array:\n");
    for(i=0; i<n; i++)
    {
        scanf("%d", &arr[i]);
        freq[i] = -1; // Initialize frequency array as -1
    }

    // Logic to find frequency of each element
    for(i=0; i<n; i++)
    {
        count = 1;
        for(j=i+1; j<n; j++)
        {
            if(arr[i] == arr[j])
            {
                count++;
                freq[j] = 0; // Mark element as visited
            }
        }
        if(freq[i] != 0)
        {
            freq[i] = count;
        }
    }
    
    // Print frequency of each element
    printf("\nFrequency of all elements of array : \n");
    for(i=0; i<n; i++)
    {
        if(freq[i] != 0)
        {
            printf("%d occurs %d times\n", arr[i], freq[i]);
        }
    }
    return 0;
}

#include <iostream>
#include <unordered_map>

using namespace std;

int main() {
    int n;
    cout << "Enter the size of array: ";
    cin >> n;

    int arr[n];
    cout << "Enter the elements of the array: ";
    for (int i = 0; i < n; i++) {
        cin >> arr[i];
    }

    // using unordered_map to store the frequency of each element
    unordered_map<int, int> freqMap;
    for (int i = 0; i < n; i++) {
        freqMap[arr[i]]++;
    }

    // printing the frequency of each element
    cout << "Frequency of each element in the array: " << endl;
    for (auto it = freqMap.begin(); it != freqMap.end(); it++) {
        cout << it->first << " : " << it->second << endl;
    }

    return 0;
}

import java.util.HashMap;

public class FrequencyOfElements {

    public static void main(String[] args) {
        
        int[] arr = {10, 20, 20, 10, 10, 30, 50, 10, 20};
        
        // Create a HashMap to store the frequency of each element
        HashMap<Integer, Integer> freqMap = new HashMap<>();
        
        // Iterate over the array and update the frequency of each element in the HashMap
        for(int i=0; i<arr.length; i++) {
            if(freqMap.containsKey(arr[i])) {
                freqMap.put(arr[i], freqMap.get(arr[i])+1);
            } else {
                freqMap.put(arr[i], 1);
            }
        }
        
        // Print the frequency of each element
        for(int key : freqMap.keySet()) {
            System.out.println(key + " occurs " + freqMap.get(key) + " times");
        }
    }

}

arr = [1, 2, 3, 2, 1, 2, 4, 5, 4, 1]

freq = {}

for i in arr:
    if i in freq:
        freq[i] += 1
    else:
        freq[i] = 1

for key, value in freq.items():
    print(key, ":", value)    

using System;

class Program {
    static void Main(string[] args) {
        int[] arr = {1, 2, 3, 1, 2, 3, 4, 5, 6, 5};
        int n = arr.Length;
        int[] freq = new int[n];
        int visited = -1;
        
        for(int i = 0; i < n; i++) {
            int count = 1;
            for(int j = i + 1; j < n; j++) {
                if(arr[i] == arr[j]) {
                    count++;
                    freq[j] = visited;
                }
            }
            if(freq[i] != visited) {
                freq[i] = count;
            }
        }
        
        Console.WriteLine("Element\tFrequency");
        for(int i = 0; i < n; i++) {
            if(freq[i] != visited) {
                Console.WriteLine(arr[i] + "\t" + freq[i]);
            }
        }
    }
}