Exercise 9.1 (Completed)

1. (Practice) Write declaration and open statements that link the following external filenames
to their corresponding internal filenames. All files are text-based.
External Filename      InternalFilename      Mode
coba.mem               memo                  output
book.let               letter                output
coupons.bnd            coups                 append
yield.bnd              yield                 append
prices.dat             priFile               input
rates.dat              rates                 input

fstream memo;
memo.open("coba.mem" , ios::out);
fstream letter;
letter.open("book.let", ios::out);
fstream coups;
coups.open("coupons.bnd", ios::app);
fstream yield;
yield.open("yield.bnd", ios::app);
fstream priFile;
priFile.open("prices.dat", ios::in);
fstream rates;
rates.open("rates.dat", ios::in);

2. (Practice) a. Write a set of two statements that declares the following objects as ifstream
objects and then opens them as text input files: inData.txt, prices.txt, coupons.dat,
and exper.dat.

ifstream inFile;
inFile.open("inData.txt");
ifstream inFile;
inFile.open("prices.txt");
ifstream inFile;
inFile.open("coupons.dat");
ifstream inFile;
inFile.open("exper.dat");

b. Rewrite the two statements for Exercise 2a, using a single statement.

ifstream inFile("inData.txt");
ifstream inFile("prices.txt");
ifstream inFile("coupons.dat");
ifstream inFile("exper.dat");


3. (Practice) a. Write a set of two statements declaring the following objects as ofstream objects
and then opening them as text output files: outDate.txt, rates.txt, distance.txt, and
file2.txt.

ofstream outFile;
outFile.open("outDate.txt");
ofstream outFile;
outFile.open("rates.txt");
ofstream outFile;
outFile.open("distance.txt");
ofstream outFile;
outFile.open("file2.txt");

b. Rewrite the two statements for Exercise 3a, using a single statement.

ofstream outFile("outDate.txt");
ofstream outFile("rates.txt");
ofstream outFile("distance.txt");
ofstream outFile("file2.txt");

4. (Practice) Enter and run Program 9.1 on your computer.

#include <string>
#include <iostream>
#include <fstream>
#include <cstdlib>   // needed for exit()
using namespace std;
int main()
{
	ifstream inFile;
	inFile.open("prices.dat");  // open the file with the
	// external name prices.dat
	if (inFile.fail())  // check for a successful open
	{
		cout << "\nThe file was not successfully opened"
			<< "\n Please check that the file currently exists."
			<< endl;
		system("PAUSE");
		exit(1);
	}
	cout << "\nThe file has been successfully opened for reading."
		<< endl;
	// statements to read data from the file are placed here		
	system("PAUSE");
		return 0;
}

5. (Practice) Enter and run Program 9.2 on your computer.

#include <iostream>
#include <fstream>
#include <cstdlib>   // needed for exit()
using namespace std;
int main()
{
	ifstream inFile;
	ofstream outFile;
	char response;
	inFile.open("prices.dat");  // attempt to open the file for input
	if (!inFile.fail())  // if it doesn't fail, the file exists
	{
		cout << "A file by the name prices.dat exists.\n"
			<< "Do you want to continue and overwrite it\n"
			<< " with the new data(y or n) : ";
		cin >> response;
		if (tolower(response) == 'n')
		{
			cout << "The existing file will not be overwritten." << endl;
			exit(1);  //terminate program execution
		}
	}
	outFile.open("prices.dat"); // now open the file for writing

	if (inFile.fail())  // check for a successful open
	{
		cout << "\nThe file was not successfully opened" << endl;
		system("PAUSE");
		exit(1);
	}
	cout << "The file has been successfully opened for output." << endl;
	
		return 0;
}

6. (Practice) a. Enter and run Program 9.3a on your computer.

#include <iostream>
#include <fstream>
#include <cstdlib>  // needed for exit()
#include <string>   // needed for the string class
using namespace std;
int main()
{
	string filename = "prices.dat"; // create and initialize a string object
	// with the filename at the top of the
	// main() function
	ifstream inFile;
		inFile.open(filename.c_str());  // open the file
	if (inFile.fail())  // check for successful open
	{
		cout << "\nThe file named " << filename
			<< " was not successfully opened"
			<< "\n Please check that the file currently exists."
			<< endl;
		system("PAUSE");
		exit(1);
	}
	cout << "\nThe file has been successfully opened for reading.\n";
	system("PAUSE");
	return 0;
}

b. Add a close() method to Program 9.3a, and then run the program.

#include <iostream>
#include <fstream>
#include <cstdlib>  // needed for exit()
#include <string>   // needed for the string class
using namespace std;
int main()
{
	string filename = "prices.dat"; // create and initialize a string object
	// with the filename at the top of the
	// main() function
	ifstream inFile;
		inFile.open(filename.c_str());  // open the file
		inFile.close();
	if (inFile.fail())  // check for successful open
	{
		cout << "\nThe file named " << filename
			<< " was not successfully opened"
			<< "\n Please check that the file currently exists."
			<< endl;
		system("PAUSE");
		exit(1);
	}
	cout << "\nThe file has been successfully opened for reading.\n";
	system("PAUSE");
	return 0;
}

7. (Practice) a. Enter and run Program 9.3b on your computer.

#include <iostream>
#include <fstream>
#include <cstdlib>   // needed for exit()
#include <string>    // needed for the string class
using namespace std;
int main()
{
	string filename; // declare a string object with no initialization
	ifstream inFile;
	cout << "Please enter the name of the file you wish to open : ";
	cin >> filename;
	inFile.open(filename.c_str());  // open the file
	if (inFile.fail())  // check for successful open
	{
		cout << "\nThe file named " << filename
			<< " was not successfully opened"
			<< "\n Please check that the file currently exists."
			<< endl;
		exit(1);
	}
	cout << "\nThe file has been successfully opened for reading.\n";
	return 0;
}

b. Add a close() method to Program 9.3b, and then run the program.

#include <iostream>
#include <fstream>
#include <cstdlib>   // needed for exit()
#include <string>    // needed for the string class
using namespace std;
int main()

{
	string filename; // declare a string object with no initialization
	ifstream inFile;
	cout << "Please enter the name of the file you wish to open : ";
	cin >> filename;
	inFile.open(filename.c_str());  // open the file
	inFile.close();
	if (inFile.fail())  // check for successful open
	{
		cout << "\nThe file named " << filename
			<< " was not successfully opened"
			<< "\n Please check that the file currently exists."
			<< endl;
		exit(1);
	}
	cout << "\nThe file has been successfully opened for reading.\n";
	return 0;
}

8. (Practice) Using the reference manuals provided with your computer’s OS, determine the following: 

a. The maximum number of characters the computer can use to name a file for storage.

255 characters is the max number of character.

b. The maximum number of data files that can be open at the same time.

512 is the max number of data files that can be open at the same time.

9. (Practice) Is calling a saved C++ program a file appropriate? Why or why not?

Yes, because everything on your computer is contained within a file.

10. (Practice) a. Write declaration and open statements to link the following external filenames
to their corresponding internal filenames. Use only ifstream and ofstream objects.
External Filename            Internal Filename              Mode
coba.mem                     memo                           binary and output
coupons.bnd                  coups                          binary and append
prices.dat                   priFile                        binary and input

ofstream memo;
memo.open("coba.mem");
ifstream coups;
coups.open("coupons.bnd");
ifstream priFile;
priFile.open("prices.dat");


b. Redo Exercise 10a, using only fstream objects.

fstream memo;
memo.open("coba.mem", ios:: out | ios::binary);
fstream coups;
coups.open("coupons.bnd", ios::app | ios::binary);
fstream priFile;
coups.open("prices.dat", ios::in | ios::binary);

c. Write close() statements for each file opened in Exercise 10a.

ofstream memo;
memo.open("coba.mem");
memo.close();
ifstream coups;
coups.open("coupons.bnd");
coups.close();
ifstream priFile;
priFile.open("prices.dat");
coups.close();