Zajęcia 8 (2025-04-14)

int chmod(const char *pathname, mode_t mode);

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

int main()
{
	if (chmod("test.c", 0644) < 0) {
		perror("chmod");
		return 1;
	}
	return 0;
}

struct stat {
	mode_t st_mode;
	...
};

int stat(const char *restrict pathname, struct stat *restrict statbuf);

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

int main()
{
	struct stat s;
	if (stat("test.c", &s) < 0) {
		perror("stat");
		return 1;
	}

	printf("test.c perm decimal: %d\n", s.st_mode);
	printf("test.c perm octal:   %o\n", s.st_mode);

	printf("test.c perm binary:  ");
	for (int i = 3 * 3 - 1; i >= 0; --i) {
		printf("%d", (s.st_mode & (1 << i)) > 0 ? 1 : 0);
	}
	printf("\n");

	return 0;
}

#include <stdio.h>
#include <assert.h>

enum when
{
	ON_MONDAY    = 0b0000001,
	ON_TUESDAY   = 0b0000010,
	ON_WEDNESDAY = 0b0000100,
	ON_THURSDAY  = 0b0001000,
	ON_FRIDAY    = 0b0010000,
	ON_SATURDAY  = 0b0100000,
	ON_SUNDAY    = 0b1000000,

	ON_WORKDAY = ON_MONDAY | ON_TUESDAY | ON_WEDNESDAY | ON_THURSDAY | ON_FRIDAY,
	ON_WEEKEND = ON_SATURDAY | ON_SUNDAY,
	EVERYDAY = ON_WORKDAY | ON_WEEKEND,
};

struct todo
{
	enum when when;
	char const *what;
};

struct todo todos[] = {
	{ .when = EVERYDAY, .what = "Drink water" },
	{ .when = ON_MONDAY, .what = "Go to the gym" },
	{ .when = ON_WEEKEND, .what = "Relax" },
};

int main()
{
	enum when today = ON_MONDAY;

	for (int i = 0; i < sizeof(todos) / sizeof(*todos); ++i) {
		struct todo todo = todos[i];
		if ((todo.when & today) == today) {
			printf("%s\n", todo.what);
		}
	}

}

#include <stdio.h>
#include <assert.h>

#define WEEKDAY_ENUM(X) \
	X(MONDAY,    1, "poniedziałek") \
	X(TUESDAY,   2, "wtorek")       \
	X(WEDNESDAY, 3, "środa")        \
	X(THURSDAY,  4, "czwartek")     \
	X(FRIDAY,    5, "piątek")       \
	X(SATURDAY,  6, "sobota")       \
	X(SUNDAY,    7, "niedziela")

enum weekday
{
#define X(label, number, name) label = number,
WEEKDAY_ENUM(X)
#undef X

	MIN_WEEKDAY = MONDAY,
	MAX_WEEKDAY = SUNDAY,
};

char const* pretty(enum weekday wd)
{
	switch (wd) {
#define X(label, number, name) case label: return name;
WEEKDAY_ENUM(X)
#undef X
	}
	static_assert(MAX_WEEKDAY - MIN_WEEKDAY == 6, "Number of days in a week has changed");
}

int main()
{
	enum weekday wd;

	do {
		printf("Wybierz dzień tygodnia: ");
		scanf("%d", &wd);
	} while (wd < MIN_WEEKDAY || wd > MAX_WEEKDAY);

	printf("Wybrano dzień tygodnia: %s\n", pretty(wd));
	return 0;
}