// lab3IOsamples.cpp
// Lab 3: Program written by Lucia Moura
// This is a program to test several methods of reading and writing

#include <iostream>
#include <fstream>
#include <string>
using namespace std;

int main() { 

  fstream file; unsigned int i;
  char c; long int num1,num2, num3; char Cstring[200];

  // In each of the following sections, we read information
  // from the same file using different methods.
  // Try to guess the outcome before running the program.

  cout<<"Session 1 using get(char):\n";
  file.open("lowcomp1.txt",ios::in);
  file.get(c); cout<<"Read:"<<c<<"\n";
  file.close();

  cout<<"Session 2 using `file>>num' 3 times:\n";
  file.open("lowcomp1.txt",ios::in);
  file>>num1; cout<<"Read:`"<<num1<<"'\n";
  file>>num2; cout<<"Read:`"<<num2<<"'\n";
  file>>num3; cout<<"Read:`"<<num3<<"'\n";
  file.close();

  cout<<"Session 3 using getline:\n";
  file.open("lowcomp1.txt",ios::in);
  file.getline(Cstring,1000,'\n'); 
  cout<<"Read:'"; 
  for(i=0; i< strlen(Cstring); i++)
     cout<<Cstring[i]; 
  cout<<"'\n";
  file.close();
 
  cout<<"Session 4 using read for 3 characters:\n";
  file.open("lowcomp1.txt",ios::in);
  file.read(Cstring,3); 
  cout<<"Read:'"; 
  for(i=0; i< 3; i++)
     cout<<Cstring[i]; 
  cout<<"'\n";
  file.close();

  cout<<"Session 5 using getline up to the delimiter '1':\n";
  file.open("lowcomp1.txt",ios::in);
  file.getline(Cstring,1000,'1'); 
  cout<<"Read:'"; 
  for(i=0; i< strlen(Cstring); i++)
     cout<<Cstring[i]; 
  cout<<"'\n";
  file.close();

  // the next piece of code tries to illustrate the difference between
  // writing integers in "text mode" or "binary mode" into a file
  // for example, if you declaire and initilize an integer like this:
  // short int i=16640; // short ints have 2 bytes
  // if you write in text mode (file<<i;) 5 characters will be written:
  //      '1','6','6','4','0'  (file size = 5 bytes)
  //       if you pick at the file you see '16640' there.
  // if you write in binary mode (file.write(&i,2);), 2 bytes will be written:
  //       the biunary representation of the # is: 0100000100000000
  //       if you pick at the file you will see two bytes, not necessarily
  //       legible to the naked eye. In this case, because 01000001 is the
  //       binary representation of character 'A', you will se an 'A' at
  //       the start of the file.
  
  fstream outfile;
  long int x;  // 4-byte integer
  short int y; // 2-byte integer

  // the numbers below where chosen, so that the bytes in the number have
  // a character representation, to facilitate visualization of file.
  
  x=65+256*65+256*256*66+256*256*256*68; 
  y=69+256*67;

  // hint: ASCII codes: A=65, B=66, C=67, D=68, E=69
  // used base `256' above as a trick to set bytes as I wished: 
  // check output files!

  outfile.open("outfile.txt", ios::out);
  outfile << x << ' ' << y;
  outfile.close();
  cout<<"Created outfile.txt. How many bytes are there in the file? \n";

  outfile.open("outfilebin.txt", ios::out|ios::binary);
  outfile.write(reinterpret_cast <char *> (&x), sizeof(long int)); 
  outfile.write(reinterpret_cast <char *> (&y), sizeof(short int));
  outfile.close();
  cout<<"Created outfilebin.txt. How many bytes are there in the file?\n";

  return 0; 
}