Different digits in number

How can I do it - with pointer and only one loop ?

for exmpl function - unsigned int dif(const char *str)

Code:

---

counter = 0;
for(i = 0; i < N; i++)                               
A[i] = 0;
do                                                               
{
      A[tmp%10]++;                               
      tmp /= 10;
}
while(tmp);
for(i = 0; i < N; i++)
if(A[i]) counter++;               
printf("\n\nThere r %u different digits in the number %u\n",counter , n);

---

Why do you need pointer for that? It can be done using one loop only.

It is unclear what you are asking for. Four words "Different digits in number" is not a description of what you want your function to achieve.
One thing for you to do would be to give us some sample inputs and outputs.
E.g. Is this what you want?

Input: 56361 Output: 5
Input: 424002 Output: 6

Or this ...

Input: 56361 Output: 4
Input: 424002 Output: 3

Or something else ...