Thread: Help Counting Amount of Different Numbers in an Array

Hi, I'm pretty new to programming and I'm having some trouble with this. I need to create a program that counts the amount of different numbers in an array, for example if the user entered the numbers: 858443 the result would be:
8 occurs 2 times
5 occurs 1 time
4 occurs 2 times
3 occurs 1 time

I can get the prgram to ask the user to enter the amount of numbers they're going to enter and I can get those numbers and store them in the array but then I'm not sure what to do. They also need to be in descending order, heres what I have so far:

Code:

#include <stdio.h>
#define NUMBERS 10
int main ()
{
int count[NUMBERS];
   int i = 0, num_st, input_ok = 0, total = 0;
   /* initialise the array */
   for (i = 0; i < NUMBERS; i++)
         count[i] = 0;
/* get the amount of numbers */
   printf("Enter the amount of numbers > ");
   
   do 
   {
          scanf("%d", &num_st);
          if (num_st >=0 && num_st <= 10)
              input_ok = 1;
         else
             printf("Error> Max number is %d, Try again \n", NUMBERS);
   }
   while (input_ok == 0);
/* get values */
   for (i = 0; i < num_st; i++){
        printf("Enter #%d > ", i+1);
        scanf("%d", &count[i]);
        total = total + count[i];
   }
}

Any help would be greatly appreciated

Am I barking up the wrong tree here altogether?

Try converting the number to string (you can use sprintf for that).

Then you can travel through that string (with a pointer) and compare each character separately, and then add to the counter.

Thanks for the reply, we haven't moved on to that stuff in class yet so I don't think I can do it. I'm wondering if I should just start again from scratch?

I think the count array is supposed to sum all the occurrences of the digits as they are entered. So if the user enters digit '8', count[8] gets incremented.
Something like:

Code:

scanf("%d", &num_st);
count[num_st]++;

What do you think? There is no need to save the digits any longer than that in an array. Just sum in one by one as they occur.

Sort your array, than you can iterate.

Note that for an integer, you can pick off the last digit by taking num%10. Then if you do newnum=num/10, the new last digits (the 10s place of the original number) is newnum%10.

If you keep modding by 10 and dividing by 10, you strip off one digit at a time which you can keep count of.

Might make for a simpler approach than storing digits in an array


Example:

User enters 5567

5567%10 = 7 - so we have a seven
5567/10 = 556
556%10 = 6 - we have a six
556/10 = 55
55%10 = 5 - we have a five
55/10 = 5
5%10 = 5 - we have another five
5/10 = 0 - we are done.