Binary I/O

/**
 *  @file p2.cpp
 *
 *  CS 150 - Command Line Arguments and Binary Files
 */

/*
1. No arguments supplied? Print an error message on standard error and exit

2. One argument? Open the input file in binary mode and print (on the console)
the name of the file followed by its size in bytes. See format below.
    • Cannot open file? Print error message (standard error) and exit
3. Two arguments? Open the second file for output (in text mode) and the
information from the first file in this file instead of to the screen.
    • Cannot open file for output? Print error message (standard error) and exit
*/

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

//////// FUNCTION PROTOTYPES

bool printBinarySize(char * filename, ostream& out);

////////////////////////////

//////////////////////////// DEFINE YOUR MAIN FUNCTION BELOW THIS LINE

int main(int argc, char * argv[])
{
    switch (argc)
    {
    case 1:
        cerr << "Usage: p2 file-to-open [file-to-save-to]" << endl;
        return 1;

        break;

    case 2:
        if (! printBinarySize(argv[1], cout)) // it still executes
            return 1;

        break;

    case 3:
        ofstream out(argv[2]);

        if (out.fail())
        {
            cerr << "Cannot open the output file " << argv[2] << " for writing.";
            return 1;
        }

        if (! printBinarySize(argv[1], out)) // it still executes
            return 1;

        break;

    }

    return 0;
}



////////////// FUNCTIONS

/*
    Function that opens a binary file, checks if it could be open,
    gets its size in bytes, and then send the size to an ostream
    object.

    Returns false if it could not open the file and true if succeded.
*/
bool printBinarySize(char * filename, ostream& out)
{
    ifstream in(filename, ios::binary | ios::in | ios::ate); //open to read and at the end

    if (in.fail())
    {
        cerr << "Cannot open the input file " << filename;
        return false;
    }

    ios::pos_type size = in.tellg(); // get posicion ATE (At The End)
    out << filename << ": size is " << size << " bytes.";

    return true;
}