number_of_digits_without_using_loop_v1.c

/*

    number_of_digits_without_using_loop_v1.c

    https://en.wikipedia.org/wiki/Logarithm
    https://www.mathsisfun.com/algebra/logarithms.html

    log(10)    = 1
    log(100)   = 2
    log(1000)  = 3
    log(10000) = 4
    . . .


    You can find all my C programs at Dragan Milicev's pastebin:

    https://pastebin.com/u/dmilicev

*/

#include <stdio.h>
#include <math.h>       // for log10()

int main(void)
{
    long long num = 999999991234567890;
    int count = 0;

    //count = ( num == 0 ) ? 1 : ( log10(num)+1 );      // or

    if( num == 0 )
        count = 1;
    else
        count = log10(num)+1;

    printf("\n In number %lld there are total digits %d \n", num, count);

    printf("\n In number %llu there are total digits %d \n", num, count);


    return 0;

} // main()