prosjek svih cifara u nizu

#include <stdio.h>
#include <stdlib.h>
#include <ctype.h>
#include <string.h>

float prosjek(int niz[], int vel)
{
    int i;
    int cifra = 0;
    int counter = 0, suma = 0;
    for(i = 0; i<vel; i++)
    {
        while(niz[i] != 0)
        {
            cifra = niz[i] % 10;
            niz[i] /= 10;
            counter++;
            suma+=cifra;
        }
    }
    return (float)suma/counter;
}




int main()
{
    int niz[3] = {1, 21, 3};
    printf("%.2f", prosjek(niz, 3));
    return 0;
}