#include <stdio.h>
#include <stdlib.h>
#include <fcntl.h>
#include <unistd.h>
#include <string.h>
#define STDOUT 1
#define STDERR 2
#define SZBUF 256


int main(int argc, char** argv){
  int descripteur, x;
  ssize_t echec;
  char buf[SZBUF];
  if (argc < 2){
    fprintf(stderr, "Usage : %s <file-name>\n",argv[0]);
    exit(1);
  }
  descripteur = open(argv[1], O_WRONLY | O_TRUNC | O_CREAT, 0600);
  if (descripteur==-1){
    perror("opening file fail !");
    exit(2);
  }
  write(1,"Numb --> ",9);
  memset(buf,0,SZBUF);
  while (echec = read(0,buf,SZBUF)){
    x = (int) strtol(buf,NULL,0);
    echec = write(descripteur,&x,4);
    if (echec==-1){
      perror("writing in file failed!");
      exit(3);
    }
    write(1,"Numb --> ",9);
    memset(buf,0,SZBUF);
  }
  close(descripteur);
  exit(0);
}