: Worker(wk), Waiter(wk,p), Singer(wk,v) {}
SingingWaiter(const Waiter & wt, int v = other)
: Worker(wt),Waiter(wt), Singer(wt,v) {}
SingingWaiter(const Singer & wt, int p = 0)
: Worker(wt),Waiter(wt,p), Singer(wt) {}
void Set();
void Show() const;
};
#endif
Listing 14.11. workermi.cpp
// workermi.cpp -- working class methods with MI
#include "workermi.h"
#include
using std::cout;
using std::cin;
using std::endl;
// Worker methods
Worker::~Worker() { }
// protected methods
void Worker::Data() const
{
cout << "Name: " << fullname << endl;
cout << "Employee ID: " << id << endl;
}
void Worker::Get()
{
getline(cin, fullname);
cout << "Enter worker's ID: ";
cin >> id;
while (cin.get() != '\n')
continue;
}
// Waiter methods
void Waiter::Set()
{
cout << "Enter waiter's name: ";
Worker::Get();
Get();
}
void Waiter::Show() const
{
cout << "Category: waiter\n";
Worker::Data();
Data();
}
// protected methods
void Waiter::Data() const
{
cout << "Panache rating: " << panache << endl;
}
void Waiter::Get()
{
cout << "Enter waiter's panache rating: ";
cin >> panache;
while (cin.get() != '\n')
continue;
}
// Singer methods
char * Singer::pv[Singer::Vtypes] = {"other", "alto", "contralto",
"soprano", "bass", "baritone", "tenor"};
void Singer::Set()
{
cout << "Enter singer's name: ";
Worker::Get();
Get();
}
void Singer::Show() const
{
cout << "Category: singer\n";
Worker::Data();
Data();
}
// protected methods
void Singer::Data() const
{
cout << "Vocal range: " << pv[voice] << endl;
}
void Singer::Get()
{
cout << "Enter number for singer's vocal range:\n";
int i;
for (i = 0; i < Vtypes; i++)
{
cout << i << ": " << pv[i] << " ";
if ( i % 4 == 3)
cout << endl;
}
if (i % 4 != 0)
cout << '\n';
cin >> voice;
while (cin.get() != '\n')
continue;
}
// SingingWaiter methods
void SingingWaiter::Data() const
{
Singer::Data();
Waiter::Data();
}
void SingingWaiter::Get()
{
Waiter::Get();
Singer::Get();
}
void SingingWaiter::Set()
{
cout << "Enter singing waiter's name: ";
Worker::Get();
Get();
}
void SingingWaiter::Show() const
{
cout << "Category: singing waiter\n";
Worker::Data();
Data();
}
Of course, curiosity demands that you test these classes, and Listing 14.12 provides code to do so. Note that the program makes use of polymorphism by assigning the addresses of various kinds of classes to base-class pointers. Also the program uses the C-style string library function strchr() in the following test:
while (strchr("wstq", choice) == NULL)
This function returns the address of the first occurrence of the choice character value in the string "wstq"; the function returns the NULL pointer if the character isn’t found. This test is simpler to write than an if statement that compares choice to each letter individually.
Be sure to compile Listing 14.12 along with workermi.cpp.
Listing 14.12. workmi.cpp
// workmi.cpp -- multiple inheritance
// compile with workermi.cpp
#include
#include
#include "workermi.h"
const int SIZE = 5;
int main()
{
using std::cin;
using std::cout;
using std::endl;
using std::strchr;
Worker * lolas[SIZE];
int ct;
for (ct = 0; ct < SIZE; ct++)
{
char choice;
cout << "Enter the employee category:\n"
<< "w: waiter s: singer "
<< "t: singing waiter q: quit\n";
cin >> choice;
while (strchr("wstq", choice) == NULL)
{
cout << "Please enter a w, s, t, or q: ";
cin >> choice;
}
if (choice == 'q')
break;
switch(choice)
{
case 'w': lolas[ct] = new Waiter;
break;
case 's': lolas[ct] = new Singer;
break;
case 't': lolas[ct] = new SingingWaiter;
break;
}
cin.get();
lolas[ct]->Set();
}
cout << "\nHere is your staff:\n";
int i;
for (i = 0; i < ct; i++)
{
cout << endl;
lolas[i]->Show();
}
for (i = 0; i < ct; i++)
delete lolas[i];
cout << "Bye.\n";
return 0;
}
Here is a sample run of the program in Listings 14.10, 14.11, and 14.12:
Enter the employee category:
w: waiter s: singer t: singing waiter q: quit
w
Enter waiter's name: Wally Slipshod
Enter worker's ID: 1040
Enter waiter's panache rating: 4
Enter the employee category:
w: waiter s: singer t: singing waiter q: quit
s
Enter singer's name: Sinclair Parma
Enter worker's ID: 1044
Enter number for singer's vocal range:
0: other 1: alto 2: contralto 3: soprano
4: bass 5: baritone 6: tenor
5
Enter the employee category:
w: waiter s: singer t: singing waiter q: quit
t
Enter singing waiter's name: Natasha Gargalova
Enter worker's ID: 1021
Enter waiter's panache rating: 6
Enter number for singer's vocal range:
0: other 1: alto 2: contralto 3: soprano
4: bass 5: baritone 6: tenor
3
Enter the employee category:
w: waiter s: singer t: singing waiter q: quit
q
Here is your staff:
Category: waiter
Name: Wally Slipshod
Employee ID: 1040
Panache rating: 4
Category: singer
Name: Sinclair Parma
Employee ID: 1044
Vocal range: baritone
Category: singing waiter
Name: Natasha Gargalova
Employee ID: 1021
Vocal range: soprano
Panache rating: 6
Bye.
Let’s look at a few more matters concerning MI.
Mixed Virtual and Nonvirtual Bases
