/*
 * Read a file that contains lines of the form
 * last, first
 * Output those lines into another file, in the
 * form first last
 * Illustrates reference parameters, input files, output files
 * This program is deliberately missing comments.
 */

#include <iostream.h>
#include <fstream.h>
#include "apstring.h"

void OpenInput( apstring & infile, ifstream & fin );
void OpenOutput( apstring infile, apstring outfile, ofstream & fout );
void CopyFiles( istream & fin, ostream & fout );
void GetNames( apstring Name, apstring & First, apstring & Last );

int main( )
{
    apstring infile;  // Input file name
    apstring outfile; // Output file name
    ifstream fin;     // Input file stream
    ofstream fout;    // Output file stream

    OpenInput( infile, fin );
    OpenOutput( infile, outfile, fout );
    CopyFiles( fin, fout );

    return 0;
}


/**
 * Usual stuff; you should copy this.
 */
void OpenInput( apstring & infile, ifstream & fin )
{
    for( ; ; )
    {
        cout << "Enter the input file name: ";
        cin >> infile;
        fin.open( infile.c_str( ), ios::in | ios::nocreate );
        if( !fin )
        {
           cout << "Bad file." << endl;
           fin.clear( );
        }
        else
           break;
    }
}


/**
 * Usual stuff. This routine also checks to
 * make sure that outfile is different from infile.
 * To avoid this test, call it with infile equal to "".
 */
void OpenOutput( apstring infile, apstring outfile, ofstream & fout )
{
    for( ; ; )
    {
        cout << "Enter the output file name: ";
        cin >> outfile;
        if( infile == outfile )
        {
            cout << "Input and output files are identical!!" << endl;
            continue;
        }
        fout.open( outfile.c_str( ) );
        if( !fout )
        {
           cout << "Bad file." << endl;
           fout.clear( );
        }
        else
           break;
    }
}


/**
 * Copy from fin to fout.
 * Uses getline to read an entire line of input in as a string.
 * Needed because there are blanks on the line.
 * getline also works with cin.
 */
void CopyFiles( istream & fin, ostream & fout )
{
    apstring Name, FirstName, LastName;

    while( !getline( fin, Name ).eof( ) )
    {
        GetNames( Name, FirstName, LastName );
        fout << FirstName << " " << LastName << endl;
    }
}


/**
 * I did this in class. Extract FirstName and LastName from Name.
 * pre: Name is of the form Last, First
 * post: LastName and FirstName are filled in.
 */
void GetNames( apstring Name, apstring & FirstName, apstring & LastName )
{
    int CommaPos = Name.find( "," );
    LastName = Name.substr( 0, CommaPos );
    FirstName = Name.substr( CommaPos + 2, Name.length( ) - ( CommaPos + 2 ) );
}