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#include <stdio.h>
#include <pthread.h>
#include <signal.h>
#include <unistd.h>

void *incrementCounter(void *counter_ptr)  {
    int *counter = (int *)counter_ptr;
    while(1) {
        printf("%d\n", *counter);
        sleep(1);
        (*counter)++;
    }
}

void *readNumber(void *counter_ptr) {
    int number;
    while(1) {
        int* counter = (int *)counter_ptr;
        if(scanf("%d", &number) == 1) {
            printf("Erhöhe den Zähler um %d\n", (int)number);
            (*counter) = (*counter) + number;
        }
        else {
            printf("Es können nur natürliche Zahlen eingegeben werden!\n");
            int ch;
			while ((ch = getchar()) != '\n' && ch != EOF)
				;
        }
    }
}

void sig_handler(int signo) {
  if (signo == SIGINT) {
      pthread_exit(NULL);
  }
}

int main () {
    int counter = 0;

    if (signal(SIGINT, sig_handler) == SIG_ERR)
      printf("\ncan't catch SIGINT\n");

    pthread_t p1, p2;
    pthread_create (&p1, NULL, incrementCounter, &counter);
    pthread_create (&p2, NULL, readNumber, &counter);

    pthread_join (p1, NULL);
    pthread_join (p2, NULL);

  printf ("\n");
  return 0;
}