Find frequency of each element in an array

Posted on Apr 24, 2020

C program to find frequency of each element in one dimensional array.

Program

#include<stdio.h>
#include<conio.h>
#define MAX 50

void read_array(int a[MAX], int n)
{
    int i;
    for(i=0;i<n;i++)
    {
        printf("Element %d\t:",i+1);
        scanf("%d",&a[i]);
    }
}

void frequency(int a[MAX], int freq[MAX], int n)
{
    int i, j, count;

    for(i=0;i<n;i++)
    {
        freq[i] = -1;
    }
    for(i=0;i<n;i++)
    {
        count = 1;
        for(j=i+1;j<n;j++)
        {
            if(a[i]==a[j])
            {
                count++;
                freq[j] = 0;;
            }
        }
        if(freq[i] != 0)
        {
            freq[i] = count;
        }
    }

    printf("\nFrequency of all the elements of the array:\n");
    for(i=0;i<n;i++)
    {
        if(freq[i] != 0)
        {
            printf("%d occurs %d times\n",a[i], freq[i]);
        }
    }
}

void main()
{
    int arr[MAX], freq[MAX];
    int i, n;

    printf("Enter the number of elements in the array\t:");
    scanf("%d",&n);

    printf("Enter the elements of the array\n");
    read_array(arr, n);

    frequency(arr, freq, n);

    getch();
}

Output

Enter the number of elements in the array       :8
Enter the elements of the array
Element 1       :1
Element 2       :2
Element 3       :3
Element 4       :2
Element 5       :1
Element 6       :4
Element 7       :2
Element 8       :4

Frequency of all the elements of the array:
1 occurs 2 times
2 occurs 3 times
3 occurs 1 times
4 occurs 2 times