Exercise 14.3 (Completed)

1. (Practice) Define the following terms:
a. Exception - is a value, a variable, or an object containing information about the error at the point the error occurs

b. try block - identifies the start of an exception-handling block of code.

c. catch block - receive a thrown exception and process it

d. Exception handler - when an error occurs while a function is executing, the function creates an exception.

e. Throw an exception - the process of generating and passing an exception

f. Catch an exception - receive a thrown exception and process it

2. (Practice) Enter and run Program 14.14.

//Done!!

#include "stdafx.h" 
#include <iostream>
using namespace std;
int main()
{
	int numerator, denominator;
	bool needDenominator = true;
	cout << "Enter a numerator(whole number only) : ";
	cin >> numerator;
	cout << "Enter a denominator(whole number only) : ";
	while (needDenominator)
	{
		cin >> denominator;
		try
		{
			if (denominator == 0)
				throw denominator;  // an integer value is thrown
		}
		catch (int e)
		{
			cout << "A denominator value of " << e << " is invalid." << endl;
			cout << "Please reenter the denominator(whole number only) : ";
			continue;  // send control back to the while statement
		}
		cout << numerator << '/' << denominator
			<< " = " << double(numerator) / double(denominator) << endl;
		needDenominator = false;
	}
	system("PAUSE");
	return 0;
}

3. (Modify) Replace the following statement in Program 14.14
cout << numerator <<'/' << denominator
     << “ = “ << double (numerator)/ double (denominator) << endl;
with the statement
cout << numerator <<'/' << denominator
     << “ = “ << numerator/denominator << endl;
and run the modified program. Enter the values 12 and 5, and explain why the result is incorrect
from the user’s viewpoint.

//Done!!
The results are incorrect because they do not contain the decimal point information required for accurate calcuations.

4. (Modify) Modify Program 14.14 so that it throws and catches the message ***Invalid input
-A denominator value of zero is not permitted***. (Hint: Review the caution at
the end of this section.)

#include "stdafx.h" 
#include <iostream>
using namespace std;
int main()
{
	int numerator, denominator;
	bool needDenominator = true;
	cout << "Enter a numerator(whole number only) : ";
	cin >> numerator;
	cout << "Enter a denominator(whole number only) : ";
	while (needDenominator)
	{
		cin >> denominator;
		try
		{
			if (denominator == 0)
				throw "***Invalid input - A zero denominator value is not permitted***";  // an integer value is thrown
		}
		catch (char e[])
		{
			cout << "A denominator value of " << e << " is invalid." << endl;
			cout << "Please reenter the denominator(whole number only) : ";
			continue;  // send control back to the while statement
		}
		cout << numerator << '/' << denominator
			<< " = " << double(numerator) / double(denominator) << endl;
		needDenominator = false;
	}
	system("PAUSE");
	return 0;
}

5. (Modify) Modify Program 14.14 so that the try and catch blocks are included in a while
statement. The while statement should provide code that continuously requests the user to
enter a denominator until a non-zero number is entered. (Hint: The prompt to enter a new
denominator should be made in the catch block immediately after the message informing the
user an invalid denominator has been entered.)

//Done Error program 14.14 try-catch method is already in a while loop that performs the required actions.

#include "stdafx.h" 
#include <iostream>
using namespace std;
int main()
{
	int numerator, denominator;
	bool needDenominator = true;
	cout << "Enter a numerator(whole number only) : ";
	cin >> numerator;
	cout << "Enter a denominator(whole number only) : ";
	while (needDenominator)
	{
		cin >> denominator;
		try
		{
			if (denominator == 0)
				throw "***Invalid input - A zero denominator value is not permitted***";  // an integer value is thrown
		}
		catch (char e[])
		{
			cout << "A denominator value of " << e << " is invalid." << endl;
			cout << "Please reenter the denominator(whole number only) : ";
			continue;  // send control back to the while statement
		}
		cout << numerator << '/' << denominator
			<< " = " << double(numerator) / double(denominator) << endl;
		needDenominator = false;
	}
	system("PAUSE");
	return 0;
}

6. (Modify) Modify Program 14.14 so that it continues to divide two numbers until the user
enters the number 999 (as a numerator or denominator) to terminate program execution.

#include "stdafx.h" 
#include <iostream>
using namespace std;
int main()
{
	int numerator, denominator;
	bool needDenominator = true;
	cout << "Enter a numerator(whole number only) : ";
	cin >> numerator;
	cout << "Enter a denominator(whole number only) : ";
	while (needDenominator)
	{
		cin >> denominator;
		try
		{
			if (denominator == 0)
				throw denominator;  // an integer value is thrown
		}
		catch (int e)
		{
			cout << "A denominator value of " << e << " is invalid." << endl;
			cout << "Please reenter the denominator(whole number only) : ";
			continue;  // send control back to the while statement
		}
		cout << numerator << '/' << denominator
			<< " = " << double(numerator) / double(denominator) << endl;
		if (numerator == 999 || denominator == 999){
			needDenominator = false; }
	}
	system("PAUSE");
	return 0;
}