헤드 퍼스트 C 10강

#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <time.h>
#include <string.h>
#include <errno.h>
#include <signal.h>

int score = 0;

void end_game(int sig)
{
printf("\n최종 점수: %i\n", score);
exit(0);
}

int catch_signal(int sig, void (*handler)(int))
{
struct sigaction action;
action.sa_handler = handler;
sigemptyset(&action.sa_mask);
action.sa_flags = 0;
return sigaction(sig, &action, NULL);
}

void times_up(int sig)
{
puts("\n시간 초과!");
raise(SIGINT);
}

void error(char* msg)
{
fprintf(stderr, "%s: %s\n", msg, strerror(errno));
exit(1);
}

int main()
{
catch_signal(SIGALRM, times_up);
catch_signal(SIGINT, end_game);
srandom(time(0));

while(1) {
int a = random() % 11;
int b = random() % 11;
char txt[4];
alarm(5);
printf("\n%i 곱하기 %i는? ", a, b);
fgets(txt, 4, stdin);
int answer = atoi(txt);
if (answer == a * b)
score++;
else
printf("\n틀렸습니다! 점수: %i\n", score);
}

return 0;
}