Counting digits using while loop

Question

I was recently making a program which needed to check the number of digits in a number inputted by the user. As a result I made the following code:

int x;            


        

Answer 1

Given a very pipelined cpu with conditional moves, this example may be quicker:

if (x > 100000000) { x /= 100000000; count += 8; }
if (x > 10000) { x /= 10000; count += 4; }
if (x > 100) { x /= 100; count += 2; }
if (x > 10) { x /= 10; count += 1; }

as it is fully unrolled. A good compiler may also unroll the while loop to a maximum of 10 iterations though.