C++ Primer Plus

1. The Wine class has a string class object member (see Chapter 4) that holds the name of a wine and a Pair object (as discussed in this chapter) of valarray objects (as discussed in this chapter). The first member of each Pair object holds the vintage years, and the second member holds the numbers of bottles owned for the corresponding particular vintage year. For example, the first valarray object of the Pair object might hold the years 1988, 1992, and 1996, and the second valarray object might hold the bottle counts 24, 48, and 144. It may be convenient for Wine to have an int member that stores the number of years. Also some typedefs might be useful to simplify the coding:

typedef std::valarray ArrayInt;

typedef Pair PairArray;

Thus, the PairArray type represents type Pair, std::valarray >. Implement the Wine class by using containment. The class should have a default constructor and at least the following constructors:

// initialize label to l, number of years to y,

// vintage years to yr[], bottles to bot[]

Wine(const char * l, int y, const int yr[], const int bot[]);

// initialize label to l, number of years to y,

// create array objects of length y

Wine(const char * l, int y);

The Wine class should have a method GetBottles() that, given a Wine object with y years, prompts the user to enter the corresponding number of vintage years and bottle counts. A method Label() should return a reference to the wine name. A method sum() should return the total number of bottles in the second valarray object in the Pair object.

The program should prompt the user to enter a wine name, the number of elements of the array, and the year and bottle count information for each array element. The program should use this data to construct a Wine object and then display the information stored in the object. For guidance, here’s a sample test program:

// pe14-1.cpp  -- using Wine class with containment

#include

#include "winec.h"

int main ( void )

{

    using std::cin;

    using std::cout;

    using std::endl;

    cout << "Enter name of wine: ";

    char lab[50];

    cin.getline(lab, 50);

    cout << "Enter number of years: ";

    int yrs;

    cin >> yrs;

    Wine holding(lab, yrs); // store label, years, give arrays yrs elements

    holding.GetBottles();   // solicit input for year, bottle count

    holding.Show();         // display object contents

    const int YRS = 3;

    int y[YRS] = {1993, 1995, 1998};

    int b[YRS] = { 48, 60, 72};

    // create new object, initialize using data in arrays y and b

    Wine more("Gushing Grape Red",YRS, y, b);

    more.Show();

    cout << "Total bottles for " << more.Label() // use Label() method

         << ": " << more.sum() << endl;          // use sum() method

    cout << "Bye\n";

    return 0;

}

And here’s some sample output:

Enter name of wine: Gully Wash

Enter number of years: 4

Enter Gully Wash data for 4 year(s):

Enter year: 1988

Enter bottles for that year: 42

Enter year: 1994

Enter bottles for that year: 58

Enter year: 1998

Enter bottles for that year: 122

Enter year: 2001

Enter bottles for that year: 144

Wine: Gully Wash

        Year    Bottles

        1988    42

        1994    58

        1998    122

        2001    144

Wine: Gushing Grape Red

        Year    Bottles

        1993    48

        1995    60

        1998    72

Total bottles for Gushing Grape Red: 180

Bye

2. This exercise is the same as Programming Exercise 1, except that you should use private inheritance instead of containment. Again, a few typedefs might prove handy. Also you might contemplate the meaning of statements such as the following:

PairArray::operator=(PairArray(ArrayInt(),ArrayInt()));

cout  << (const string &)(*this);

The class should work with the same test program as shown in Programming Exercise 1.

3. Define a QueueTp template. Test it by creating a queue of pointers-to-Worker (as defined in Listing 14.10) and using the queue in a program similar to that in Listing 14.12.

4. A Person class holds the first name and the last name of a person. In addition to its constructors, it has a Show() method that displays both names. A Gunslinger class derives virtually from the Person class. It has a Draw() member that returns a type double value representing a gunslinger’s draw time. The class also has an int member representing the number of notches on a gunslinger’s gun. Finally, it has a Show() function that displays all this information.