C#: Count frequency of each element of an array

Last update on August 22 2025 12:42:38 (UTC/GMT +8 hours)

Write a C# Sharp program to count the frequency of each element in an array.

C# Sharp: Count frequency of each element of an array

Sample Solution:-

C# Sharp Code:

using System;

public class Exercise8
{
    public static void Main()
    {
        int[] arr1 = new int[100];  // Array to store elements
        int[] fr1 = new int[100];   // Array to store frequency
        int n, i, j, ctr;  // Variables for size, loop control, and frequency counting

        Console.Write("\n\nCount the frequency of each element of an array:\n");
        Console.Write("----------------------------------------------------\n");

        Console.Write("Input the number of elements to be stored in the array :");
        n = Convert.ToInt32(Console.ReadLine());  // Read the number of elements

        Console.Write("Input {0} elements in the array :\n", n);
        for (i = 0; i < n; i++)
        {
            Console.Write("element - {0} : ", i);
            arr1[i] = Convert.ToInt32(Console.ReadLine());  // Read elements into the array
            fr1[i] = -1;  // Initialize frequency array with -1
        }

        // Count frequency of each element
        for (i = 0; i < n; i++)
        {
            ctr = 1;  // Initialize counter to 1
            for (j = i + 1; j < n; j++)
            {
                if (arr1[i] == arr1[j])  // If current element matches other elements
                {
                    ctr++;  // Increment frequency counter
                    fr1[j] = 0;  // Mark duplicates by setting their frequency to 0
                }
            }

            if (fr1[i] != 0)  // If not a duplicate
            {
                fr1[i] = ctr;  // Store the frequency
            }
        }

        // Display frequency of each element
        Console.Write("\nThe frequency of all elements of the array : \n");
        for (i = 0; i < n; i++)
        {
            if (fr1[i] != 0)  // If frequency is not 0 (indicating duplicate)
            {
                Console.Write("{0} occurs {1} times\n", arr1[i], fr1[i]);  // Display element and its frequency
            }
        }
    }
}

Sample Output:

Count the frequency of each element of an array:                                                              
----------------------------------------------------                                                          
Input the number of elements to be stored in the array :3                                                     
Input 3 elements in the array :                                                                               
element - 0 : 10                                                                                              
element - 1 : 15                                                                                              
element - 2 : 10                                                                                               
The frequency of all elements of the array :                                                                  
10 occurs 2 times                                                                                             
15 occurs 1 times

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