NCERT Solutions for Class 12 Computer And Communication Technology Computer Science With C++ Chapter 4 Constructor And Destructor

Differentiate between Constructor and Destructor functions giving suitable example using a class in C++. When does each of them execute?

Answer the questions (i) to (iv) based on the following:

class PRODUCT
{
	int Code;
	char Item[20];
protected:
	float Qty;
public:
	PRODUCT();
	void GetIn(); void Show();
};
class WHOLESALER
{
	int WCode;
protected:
	char Manager[20];
public:
	WHOLESALER();
	void Enter();
	void Display();
};
class SHOWROOM : public PRODUCT, private WHOLESALER
{
	char Name[20],City[20];
public:
	SHOWROOM();
	void Input();
	void View();
}

(i)Which type of Inheritance out of the following is illustrated in the above example?
– Single Level Inheritance
– Multi Level Inheritance
– Multiple Inheritance

(ii) Write the names of all the data members, which are directly accessible from the member functions of class SHOWROOM.

(iii) Write the names of all the member functions, which are directly accessible by an object of class SHOWROOM.

(iv) What will be the order of execution of the constructors, when an object of class SHOWROOM is declared?

What is a copy constructor ? Give a suitable example in C++ to illustrate with its definition within a class and a declaration of an object with the help of it.

Observe the following C++ code and answer the question.

class Traveller
{
	long PNR;
	char TName[20];
public :
	Traveller() ...Function 1
	{
		cout<<'Ready'<<end1;
	}
	void Book(long P,char N[])...Function 2
	{
		PNR = P; strcpy(TName, N);
	}
	void Print() ...Function 3
	{
		cout<

Fill in the blank statements in Line 1 and Line 2 to execute Function 2 and Function 3 respectively in the following code:

void main()
{
	Traveller T;
 _________ ...Line 1
 _________ ...Line 2
 }...Stops here 

Observe the following C++ code and answer the question.

class Traveller
{
	long PNR;
	char TName[20];
public :
	Traveller() //Function 1
	{
		cout<<'Ready'<<end1;
	}
	void Book(long P,char N[])//Function 2
	{
		PNR = P; strcpy(TName, N);
	}
	void Print() //Function 3
	{
		cout<<PNR << TName <<end1;
	}
	~Traveller() //Function 4
	{
		cout<<'Booking cancelled!'<<end1;
	}
};

Which function will be executed at }//Stops here? What is this function referred as?

Write the definition of a class PIC in C++ with the following description :

Private Members
– Pno            //Data member for Picture Number (an integer)
– Category      //Data member for Picture Category (a string)
– Location     //Data member for Exhibition Location (a string)
– FixLocation //A member function to assign
             //Exhibition Location as per category
            //as shown in the following table

Public Members
– Enter()    //A function to allow user to enter values
            //Pno, category and call FixLocation() function
– SeeAll() //A function to display all the data members

Answer the questions (i) to (iv) based on the following:

class Exterior
{
	int OrderId;
	char Address[20];
protected:
	float Advance;
public:
	Exterior();
	void Book(); 
	void View();
};
class Paint:public Exterior
{
	int WallArea,ColorCode;
protected:
	char Type;
public:
	Paint();
	void PBook();
	void PView();
};
class Bill : public Paint
{
	float Charges;
	void Calculate();
	public :
	Bill();
	void Billing();
	void Print();
};

(i) Which type of Inheritance out of the following is illustrated in the above example?
– Single Level Inheritance
– Multi-Level Inheritance
– Multiple Inheritance

(ii) Write the names of all the data members, which are directly accessible from the member functions of class Paint.

(iii) Write the names of all the member functions, which are directly accessible from an object of class Bill.

(iv) What will be the order of execution of the constructors, when an object of class Bill is declared?