#include <stdio.h>
#include <sys/types.h>
#include <sys/stat.h>

//  COMPILE WITH:
//      cc -std=c11 -Wall -Werror showmode showmode.c
//  RUN WITH:
//      ./showmode  [pathname1 pathname2 .....]

void showmode(char *desc, unsigned int x)
{
#define NBITS   ((sizeof x) * NBBY)

    static char bits[NBITS+1];
    char        *b = bits;

    for(int n=NBITS-1 ; n>=0 ; --n) {
        *b = ((x & (1<<n)) ? '1' : '0');
        ++b;
    }
    *b  = '\0';
    printf("%30s\t%8u\t%s\n", desc, x, bits);
}

int main(int argc, char *argv[])
{
    for(int a=1 ; a<argc ; ++a) {
        struct stat  statbuffer;
        unsigned int x;

        if(stat(argv[a], &statbuffer) != 0) {
            continue;
        }

        x = statbuffer.st_mode;
        showmode("st_mode", x);

        x = S_IFMT;
        showmode("S_IFMT", x);

        x = statbuffer.st_mode & S_IFMT;
        showmode("st_mode & S_IFMT", x);

        x       = S_IFDIR;
        showmode("S_IFDIR", x);

        x = (statbuffer.st_mode & S_IFMT) == S_IFDIR;
        showmode("(st_mode & S_IFMT) == S_IFDIR", x);

        x       = S_IFREG;
        showmode("S_IFREG", x);

        x = (statbuffer.st_mode & S_IFMT) == S_IFREG;
        showmode("(st_mode & S_IFMT) == S_IFREG", x);

        if(S_ISDIR(statbuffer.st_mode)) {
            printf("%s is a directory\n", argv[a]);
        }
        else if(S_ISREG(statbuffer.st_mode)) {
            printf("%s is a regular file\n", argv[a]);
        }
    }
    return 0;
}