#include <stdio.h>
#include <unistd.h>
#include <sys/wait.h>
#include <fcntl.h>
#include <string.h>

#define DEFAULT_NUM_LEN 512

char *itoa(long num, char *strnum, size_t size){
  int isNegative = 0;

  
  if(num == 0){
    strnum[0] = '0';
    strnum[1] = '\0';
    return strnum;
  }
  
  if(num < 0){
    isNegative = 1;
    num = -num;
  }
  
  int counter = 0;
  while(num > 0 && counter <(int)(size-1)){
      strnum[counter] = num % 10 + '0';
      num /= 10;
      counter ++;
  }
  
  if(isNegative){
    strnum[counter] = '-';
    counter++;
  } 
  
  strnum[counter] = '\0';
  
  for(int i=0; i<counter/2; i++){
    char temp = strnum[i];
    strnum[i] = strnum[counter-1-i];
    strnum[counter-1-i] = temp; 
  }

  return strnum;
}

int main(){
  int fd = open("count_file.txt",O_CREAT | O_WRONLY | O_TRUNC,0600);
  long count = 0; 
  char intstr[DEFAULT_NUM_LEN];
  while(1){
    pid_t pid = fork();
    
    if(pid < 0){
      perror("fork");
      break;
    }

    if(pid == 0){
      sleep(100);
      return 0;
    }

    count++;
    lseek(fd,0,SEEK_SET);
    memset(intstr,0,sizeof(intstr));
    itoa(count,intstr,DEFAULT_NUM_LEN);
    write(fd,intstr,strlen(intstr));
  }
  
  close(fd);
  printf("Max forks: %ld\n",count);

  while(wait(NULL) > 0);
  

  return 0;
}