determining # of digits

[glowstick]

i need to fnid out how many digits make up a number.
i thought about using modulus first but figured that wouldnt work.
have i overlooked a built-in function ??

[moi]

the fastest brute force way to do this is actually a long string of conditionals, but unless there's some urgent need for speed, use a loop and divide by 10, something like

while (number > 0)
{
digits++;
number = number / 10;
}

[glowstick]

what if the number is 00000. there are 5 digits.
00000 = 0 and wont be divided by 10.

[moi]

Originally posted by glowstick
what if the number is 00000. there are 5 digits.

no it doesnt, 00000 has 0 digits just like 0.

[glowstick]

00000 has 5 digits.

[Azuth]

Is it user input or data within the program?
If it's user input, capture it as a string, validate that digits have been entered, then use something like strlen to get the size of the string (or count array elements, whatever). Then use atoi or similar to turn it into a number if that's what you need.

[quzah]

int numlen( int num )
{
    char buf[BUFSIZ]={0};

    sprintf(buf, "%d", num );
    return strlen( buf );
}

I'm lazy.

Quzah.

[glowstick]

Originally posted by Azuth
Is it user input or data within the program?
If it's user input, capture it as a string, validate that digits have been entered, then use something like strlen to get the size of the string (or count array elements, whatever). Then use atoi or similar to turn it into a number if that's what you need.

that'll work. thanks.

[swoopy]

Or:
#include <math.h>
.
.
int num_of_digits;
num_of_digits = (int) log10((double) num) + 1;

[Hammer]

If you're wanting to count the leading zero's, I can't see any amount of maths giving you the answer.... the only way, as already posted, is using a string (char array).

[glowstick]

Originally posted by Hammer
If you're wanting to count the leading zero's, I can't see any amount of maths giving you the answer.... the only way, as already posted, is using a string (char array).

thats what i have decided to do and it works lie a charm. in fact i just left it as a char array and printed as a string.