/*
 * I'm doing "clever" things below to account for the fact that the boolean
 * values in C differ from the exit statuses, but they're both ints and they
 * look similar (zero and one), so cleverness is possible.  I'm not sure
 * whether this is a good idea.
 */

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


int main(int argc, char **argv)
{
    extern int fexists(char *file), usage();

    if (argc == 3 && strcmp(argv[1], "-f") == 0)
	return(fexists(argv[2]));
    else if (argc != 4)
	return(usage());
    else if (strcmp(argv[2], "-lt") == 0)
	return(!(atoi(argv[1]) < atoi(argv[3])));
    else if (strcmp(argv[2], "-eq") == 0)
	return(!(atoi(argv[1]) == atoi(argv[3])));
    else if (strcmp(argv[2], "!=") == 0)
	return(!strcmp(argv[1], argv[3]));
    else if (strcmp(argv[2], "=") == 0)
	return(!!strcmp(argv[1], argv[3]));
    else
	return(usage());
}


int fexists(char *file)
{
    struct stat statbuf;
    return(lstat(file, &statbuf) < 0 || !S_ISREG(statbuf.st_mode));
}


int usage()
{
    fprintf(stderr, "usage: test { -f file | item1 {-lt|-gt|=|!=} item2 }\n");
    return(2);  /* for the exam, it's ok if you used exit status of 1 here */
}