How can I count the digits in an integer without a string cast?

Question

I fear there\'s a simple and obvious answer to this question. I need to determine how many digits wide a count of items is, so that I can pad each item number with the m

Answer 1

Okay, I can't resist: use /=:

#include 

int
main(){
        int num = 423;
        int count = 1;
        while( num /= 10)
                count ++;
        printf("Count: %d\n", count);
        return 0;
}
534 $ gcc count.c && ./a.out
Count: 3
535 $