///////////////////////////////////////////////////////
//
//	files.cpp
//
//	This program illustrates, very briefly, the
//	use of the ifstream class to read from a file,
//	and the ofstream class to write to a file.
//
//	Revision history:
//		2/16/98 (Jeff Ondich) First version.
//		10/22/99 (JO) Reorganized for clarity.
//		1/12/01 (JO) Rewrote to correspond better
//				to Savitch textbook.  In particular,
//				used open() rather than constructor.
//
////////////////////////////////////////////////////////

#include	<fstream>
#include	<string>

// Prototypes.

void InputFileExample( void );
void OutputFileExample( void );

int main( void )
{
	InputFileExample();
	OutputFileExample();
	return( 0 );
}


////////////////////////////////////////////////////////
//	Gets a file name from the user, reads the
//	words from the file and prints them, one per
//	line, to cout.  If the file named by the user
//	does not exist, an error message is printed
//	and the program halts.
////////////////////////////////////////////////////////

void InputFileExample( void )
{
	// Get the file name from the user.
	string	fileName;

	cout << "From which file would you like to read? ";
	cin >> fileName;


	// Declare an ifstream object with fileName as
	// a constructor parameter to attempt to open
	// the named file.  Check to make sure it
	// was opened successfully.

	ifstream	myFile;
	myFile.open( fileName.c_str() );
	if( !myFile.is_open() )
	{
		cout << "Trouble opening " << fileName << endl;
		exit(1);
	}

	// (Technical note:  The function open() expects its
	// parameter to be not a string, but a "char *".  That is,
	// it expects what is usually called a "C string" to distinguish
	// it from a "C++ string".  Fortunately, C++ has a way
	// to change C++ string temporarily into a C string.
	// You use the c_str() function, as shown above.)


	// Read words one at a time from the file, and
	// print them out, one per line.  The end of
	// file is reached only after an attempt to read
	// past the last character.

	string	word;
	while( myFile >> word )
	{
		cout << word << endl;
	}


	// Clean up after yourself.
	myFile.close();
}


////////////////////////////////////////////////////////
//	Gets a file name from the user and writes a
//	foolish message into the file.  If opening the
//	file fails, the program halts.
////////////////////////////////////////////////////////

void OutputFileExample( void )
{
	// Get the file name from the user.
	string	fileName;

	cout << "To which file would you like to write? ";
	cin >> fileName;


	// Declare and open an ofstream object
	// using the named file.  Check to make sure it
	// was opened successfully.  (See InputFileExample
	// for an explanation of "c_str()".)

	ofstream	myFile;
	myFile.open( fileName.c_str() );
	if( !myFile.is_open() )
	{
		cout << "Trouble opening " << fileName << endl;
		exit(1);
	}

	// Write something to the file.
	
	myFile << "Nurse, I spy gypsies. Run!" << endl;
	myFile << "Ma, I say!  Lee's as eely as I am!" << endl;
	myFile << "Satan, oscillate my metallic sonatas." << endl;
	myFile << "Go hang a salami.  I'm a lasagna hog." << endl;
	myFile << "Flee to me, remote elf." << endl;

	// Clean up after yourself.
	myFile.close();
}