pinh.c

/* Compile with gcc -Wall -o pinh pinh.c -lm
     The formulator of the pinhole camera
     microscopic probgramme by The Lightning Stalker ©April 11, 2022
     It's basically in case I can't remember the formula.'*/

#include <math.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>

int main (int argc, char **argv)
{
    if (argc == 3)
    {
        printf ("%fmm\n", 2000 * sqrt(atof(argv[2]) * (atof(argv[1]) / 1e9)));
        return (0);
    }
    else if (argc == 4 && strcmp(argv[1], "-l") == 0)
    {
      printf ("%fm\n", pow(atof(argv[3]) / 2000, 2) / (atof(argv[2]) / 1e9));
      return (0);
    }
    else  // usage text
    {
        puts ("\
Usage: pinh wavelength(nm) focal_length(m)\n\
Pinhole camera aperture calculator.\n\
Output is pinhole diameter in millimeters\n\
\n\
550nm is good rule of thumb for the visible spectrum.\n\
Example: pinh 413.000 0.95\n\
Output should be: 1.252757mm");

        return (1);
    }
}