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#include "csapp.h"
#include "terminal.h"
#include <string.h>
#include <errno.h>
#undef MAXLINE
#define MAXLINE 120
static sigjmp_buf env;
static void signal_handler(int signo) {
siglongjmp(env, signo);
}
/* If interrupted by signal, returns signal number. Otherwise converts user
* provided string to number and saves it under num_p and returns zero. */
static int readnum(int *num_p) {
char line[MAXLINE];
int n;
/* TODO: Something is missing here! Use Read() to get line from user. */
volatile static int ret_val;
ret_val = sigsetjmp(env, 1);
if (ret_val != 0) return ret_val;
alarm(1);
n = Read(STDIN_FILENO, line, MAXLINE - 1);
alarm(0);
line[n] = 0;
*num_p = atoi(line);
return 0;
}
static void game(void) {
int tty = tty_open();
int timeout = 0, num1 = 0, num2 = 0, sum;
int last_sig = 0;
int lives = 3;
int score = 0;
while (lives > 0) {
switch (last_sig) {
case 0:
timeout = 5;
num1 = random() % 100;
num2 = random() % 100;
printf("What is the sum of %d and %d?\n", num1, num2);
break;
case SIGINT:
printf(CHA(1) EL() "Bye bye!\n");
exit(EXIT_FAILURE);
case SIGALRM:
timeout--;
if (timeout < 0) {
last_sig = 0;
lives--;
printf(CHA(1) EL() "Answer was %d!\n", num1 + num2);
continue;
}
break;
default:
app_error("lastsig = %d not handled!\n", last_sig);
break;
}
/* Rewrite user prompt to show current number of lives and timeout. */
sigset_t set, oldset;
sigemptyset(&set);
sigaddset(&set, SIGINT);
sigaddset(&set, SIGALRM);
Sigprocmask(SIG_BLOCK, &set, &oldset);
int x, y;
tty_curpos(tty, &x, &y);
dprintf(STDOUT_FILENO, CHA(1) "lives: %d timeout: %d > ", lives, timeout);
if (last_sig == SIGALRM)
dprintf(STDOUT_FILENO, CHA(%d), y);
Sigprocmask(SIG_SETMASK, &oldset, NULL);
/* Read a number from user. */
last_sig = readnum(&sum);
if (last_sig)
continue;
/* Line contains user input (a number) terminated with '\0'. */
if (sum == num1 + num2) {
printf("Correct!\n");
score++;
} else {
printf("Incorrect!\n");
lives--;
}
}
Close(tty);
printf("Game over! Your score is %d.\n", score);
}
int main(void) {
/* Initialize PRNG seed. */
struct timeval tv;
gettimeofday(&tv, NULL);
srandom(tv.tv_usec);
/* SIGALRM is used for timeouts, SIGINT for graceful exit. */
Signal(SIGALRM, signal_handler);
Signal(SIGINT, signal_handler);
game();
return EXIT_SUCCESS;
}
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