C++ Nested Classes

A class declared inside a class is called nested class. A nested class can be declared under any access modifier like private, public and protected. A nested class is a member of an enclosing class and has all rights like other members. If a nested class is declared under private access modifier, then we can't access nested class outside of the enclosing class.

General Syntax of Nested Classes in C++

class A

{

Access Modifier:

    class B

    {

        ......

        ......

    Access Modifier:

        class C

        {

            ......

            ......

            ......

        };

    };

};

Example of Nested Classes in C++

#include<iostream>

#include<string.h>

using namespace std;

/*Enclosing class*/

class Student

{

private:

    int roll_no;

    char name[20];

    /*Nested class*/

    class Address

    {

    private:

        char country[20];

        char city[20];

    public:

        void setAddress(char *co, char *ci)

        {

            strcpy(country, co);

            strcpy(city, ci);

        }

        void showAddress()

        {

            cout<<"Address Details:";

            cout<<"\n  Country      : "<<country;

            cout<<"\n  City         : "<<city;

        }

    };

    Address A1;

public:

    void setRollno(int n)

    {

        roll_no = n;

    }

    void setName(char *n)

    {

        strcpy(name, n);

    }

    void setAddress(char *co, char *ci)

    {

        A1.setAddress(co, ci);

    }

    void showRollno()

    {

        cout<<"Roll Number    : "<<roll_no<<endl;

    }

    void showName()

    {

        cout<<"Name of Student: "<<name<<endl;

    }

    void showAddress()

    {

        A1.showAddress();

    }

};

int main()

{

    Student stud1;

    stud1.setRollno(10);

    stud1.setName("John");

    stud1.setAddress("Australia", "Sydney");

    stud1.showRollno();

    stud1.showName();

    stud1.showAddress();

    return 0;

}

OUTPUT:

Roll Number    : 10

Name of Student: John

Address Details:

  Country      : Australia

  City         : Sydney