Class Nesting

The C++ language allows you to create a class inside of another. This technique is referred to as nesting. At the time of this writing, nesting a class B inside of a class A doesn't give any access privilege of class A' member variables and methods to class B. Therefore, there is no major advantage to do it, only a matter of convenience and probably personal preference and opinion. It is said that the next C++ standard will allow a nested class B to have access to the private member variables and methods of the nesting class A.

(As you can see, this program was created in Borland C++ Builder. If you are using another compiler, remove the #pragma and probably the conio lines)

//---------------------------------------------------------------------------
#include <iostream>
#include <conio>
using namespace std;
#pragma hdrstop

//---------------------------------------------------------------------------

#pragma argsused
const int Maximum = 100;
//---------------------------------------------------------------------------
class TListOfStudents
{
public:
    class TStudent
    {
    private:
        string FullName;
        int    Age;
        char   Gender;
    public:
        void   setFullName(const string Name) { FullName = Name; }
        string getFullName() const { return FullName; }
        void   setAge(const int a) { Age = a; }
        int    getAge() const { return Age; }
        void   setGender(const char g) { Gender = g; }
        char   getGender() const { return Gender; }
        TStudent();
        TStudent(string FName, int a, char g);
        inline virtual ~TStudent() {}
    };
private:
    TStudent Item[Maximum];

public:
    TListOfStudents() : Count(0){}
    inline ~TListOfStudents() {}
    void Add(const TStudent& d);
    TStudent Retrieve(const int n);
    int Count;
};
//---------------------------------------------------------------------------
TListOfStudents::TStudent::TStudent()
{
    FullName = "";
    Age      = 0.00;
    Gender   = 'M';
}
//---------------------------------------------------------------------------
TListOfStudents::TStudent::TStudent(string FName, int a, char g)
{
    FullName = FName;
    Age      = a;
    Gender   = g;
}
//---------------------------------------------------------------------------
void __fastcall TListOfStudents::Add(const TStudent& d)
{
    if( Count < Maximum )
    {
	Item[Count] = d;
	Count++;
    }
}
//---------------------------------------------------------------------------
TListOfStudents::TStudent TListOfStudents::Retrieve(const int n)
{
    return Item[n];
}
//---------------------------------------------------------------------------
void __fastcall DisplayList(TListOfStudents &List);
void __fastcall CreateList(TListOfStudents &List);
//---------------------------------------------------------------------------
int main(int argc, char* argv[])
{
    TListOfStudents ListOfItems;

    CreateList(ListOfItems);
	
    DisplayList(ListOfItems);

    return 0;
}
//---------------------------------------------------------------------------
void CreateList(TListOfStudents &ListOfItems)
{
	TListOfStudents::TStudent Pupil;

	Pupil.setFullName("Harry Seamen");
	Pupil.setAge(12);
	Pupil.setGender('M');
	ListOfItems.Add(Pupil);

	Pupil.setFullName("Hermine Grand");
	Pupil.setAge(14);
	Pupil.setGender('F');
	ListOfItems.Add(Pupil);

	Pupil.setFullName("Ronald Hannah");
	Pupil.setAge(18);
	Pupil.setGender('M');
	ListOfItems.Add(Pupil);

	Pupil.setFullName("Johnny Hancock");
	Pupil.setAge(16);
	Pupil.setGender('M');
	ListOfItems.Add(Pupil);

}
//---------------------------------------------------------------------------
void DisplayList(TListOfStudents &ListOfItems)
{
	cout << "Full Name\tAge\tGender";
	string Gender[] = { "Male", "Female", "Unknown" };

	for(int i = 0; i < ListOfItems.Count; i++)
	{
		cout << "\n" << ListOfItems.Retrieve(i).getFullName()
		     << "\t" << ListOfItems.Retrieve(i).getAge()
		     << "\t";
		switch(ListOfItems.Retrieve(i).getGender())
		{
		case 'm':
		case 'M':
			cout << Gender[0];
			break;
		case 'f':
		case 'F':
			cout << Gender[1];
			break;
		default:
			cout << Gender[2];
		}
	}
}
//---------------------------------------------------------------------------