BUT2/SCR/TP03/ex5.c

#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <sys/wait.h>

#define SIZE 1000
int search0(const unsigned char * t,int start,int end)
{
  int i;
  for (i=start; i<end; i++){
    if (t[i]==0){
      return 1;
    }
  }
  return 0;
}

int search1(const unsigned char * t,int start,int end)
{
  int milieu = (end-start)/2;
  int pid = fork();
  int i;
  int status;

  
  if (pid < 0){
    return 0;
  }
  if (pid == 0){
    exit(search0(t,start,milieu+1));
  }
  if (pid > 0){
    if (search0(t,milieu+1,end)){
      return 1;
    }
    wait(&status);
    return WEXITSTATUS(status);
  }
  return 0;
}

int search2(const unsigned char * t,int start,int end)
{
  int i;
  int nbFils;
  int taille = (end-start);
  int pid;
  int status;

  printf("Enter a number between 0 and 100: ", SIZE);
  scanf(" %d", &nbFils);
    for (int i=0; i<nbFils; i++){
      pid = fork();
      if (pid < 0){
	exit(0);
      }
      if (pid == 0){
	exit(search0(t, i*taille/nbFils, (i+1)*taille/nbFils));
      }
    }
    for (int i=0; i<nbFils; i++){
      wait(&status);
      if (WEXITSTATUS(status) == 1){
	return 1;
      }
    }
    return 0;
}

int search3(const unsigned char * t,int start,int end)
{
  int i;
  int nbFils;
  int taille = (end-start);
  int pid;
  int status;

  printf("Enter a number between 0 and 100: ", SIZE);
  scanf(" %d", &nbFils);

  int* child_pids = (int*) malloc(sizeof(int) * nbFils);
  
    for (int i=0; i<nbFils; i++){
      pid = fork();
      if (pid < 0){
	exit(0);
      }
      if (pid == 0){
	exit(search0(t, i*taille/nbFils, (i+1)*taille/nbFils));
      }
      child_pids[i] = pid;
    }
    for (int i=0; i<nbFils; i++){
      wait(&status);
      if (WEXITSTATUS(status) == 1){
        for (int j = 0; j < nbFils; j++) {
	  kill(child_pids[j], SIGTERM);
        }
	return 1;
      }
    }
    return 0;
}

int main(int argc , char * argv[])
{
	unsigned char arr[SIZE];
	int i;

	srandom(time(NULL));

	for (i = 0; i < SIZE; i++)
		arr[i] = (unsigned char) (random() % 255) + 1;

	printf("Enter a number between 0 and %d: ", SIZE);
	scanf(" %d", &i);
	if (i >= 0 && i < SIZE) arr[i] = 0;

	if (search3(arr,0,SIZE-1)) 
		printf("Found !\n");
	else 
		printf("Not found !\n");
	return EXIT_SUCCESS;
}