#include <iostream>  // so I can do reasonable i/o

#include <sys/types.h>  // open at least
#include <sys/stat.h>   // open
#include <fcntl.h>      // open
#include <unistd.h>     // read

#include <string.h>  // strcmp
#include <stdio.h>   // perror

const int BUFFER_SIZE = 1024;

using namespace std;

int main(int argc, char * argv[]) {
   int inputFD, 
       outputFD, 
       openFlags;

   mode_t filePerms;

   int anInt = 5;
   float aFloat = 3.14159;
   char letter = 'c';
   string aWord ="Hello World";

   ssize_t numWritten;
   char buf[BUFFER_SIZE];

   // open the input file.
   openFlags = O_CREAT | O_WRONLY | O_TRUNC;

   // rw-rw-rw-
   filePerms = S_IRUSR | S_IWUSR | 
               S_IRGRP | S_IWGRP |
               S_IROTH | S_IWOTH; 
   outputFD = open("datafile.dat", openFlags, filePerms);

   if (outputFD == -1){
       perror("Could not open the output file ");
       return 1;
   }

   numWritten = write(outputFD, &anInt, sizeof(int));
   numWritten = write(outputFD, &aFloat, sizeof(float));
   numWritten = write(outputFD, &letter, sizeof(char));
   // add 1 to the length to get the null.
   numWritten = write(outputFD, aWord.c_str(), sizeof(char)*(aWord.size()+1));

   if (close(outputFD) == -1) {
       perror("Fail on closing output file");
       return 1;
   }

   return 0;
}