C++ 49: Containership

• It is also called as container classes or composition or nested classes or member classes for aggregation or collection.
• Container ship represents has a relationship.
• Contains object of data member such a mechanism is called as containership.

Example:

Use the concept of container ship to design a class student with data paper roll number name date of birth department. define Member function get info and show in. 

#include <iostream>
#include <conio.h>
using namespace std;
class Date
{
private:
    int D, M, Y;
public:
    void readData()
    {
        cout << "Enter Date (DD/MM/YYYY): ";
        cin >> D;
        cin.ignore();
        cin >> M;
        cin.ignore();
        cin >> Y;
    }
    void showData()
    {
        cout << "Date: " << D << " : " << M << " : " << Y << endl;
    }
};
class Student
{
private:
    int RN;
    char N[20], DEP[10];
    Date DOB;
public:
    void getInfo()
    {
        cout << "Enter student ROll: " << endl;
        cin >> RN;
        cout << "Enter student Name: " << endl;
        cin.sync();
        cin >> N;
        cout << "Enter Dept: ";
        cin >> DEP;
        DOB.readData();
    }
    void showData()
    {
        cout << "\nDisplaying Student Data\n"
             << endl;
        cout << "Roll No: " << RN << endl;
        cout << "Name: " << N << endl;
        cout << "Dept: " << DEP << endl;
        DOB.showData();
    }
};
main()
{
    Student a;
    a.getInfo();
    a.showData();
    return 0;
}

Output:

Enter student ROll: 
1022
Enter student Name:
Jack
Enter Dept: CSE
Enter Date (DD/MM/YYYY): 24/03/2002

Displaying Student Data

Roll No: 1022
Name: Jack
Dept: CSE
Date: 24 : 3 : 2002