Write C program to count number of each element in an array

#include <stdio.h>

int main()
{
    int arr[100], frequency[100];
    int i, j, count, num;

    //Enter size of array
    printf("Enter size of array: ");
    scanf("%d", &num);

    //Reading elements of array
    printf("Enter elements in array: ");
    for(i=0; i<num; i++)
    {
        scanf("%d", &arr[i]);

        //Initially initialize frequency variable to -1
        frequency[i] = -1;
    }

     for(i=0; i<num; i++)
    {
        count = 1;
        for(j=i+1; j<num; j++)
        {
        //If duplicate element is found
        if(arr[i]==arr[j])
            {
                count++;

                //Make sure not to count frequency of same element again
                frequency[j] = 0;
            }
        }

        //If frequency of current element is not counted
        if(frequency[i] != 0)
        {
            frequency[i] = count;
        }
    }

    //Print frequency of each element
    printf("\nFrequency of all elements of array : \n");
    for(i=0; i<num; i++)
    {
      if(frequency[i] != 0)
        {
            printf("%d occurs %d times\n", arr[i], frequency[i]);
        }
    }

       return 0;
}

Result