Important Questions for Class 12 Computer Science (C++) – Classes and Objects

Important Questions for Class 12 Computer Science (C++) – Classes and Objects

Previous years Examination Questions
2 Marks Questions

Question 1:
What is the relationship between a class and an object? Illustrate with a suitable example. Delhi 2013C
Аnswers:
Class
• It is a user-defined data type.
• It is a logical framework that combines data and function into a single unit.
e.g

class GABS 
{
int a,b; 
public:
void set() 
{
a=10; 
b=20;
}
void show()
{
cout<<"Value of a and b is"<<a<<b<<endl;
};

Object
• It is an instance of a class.
• It is a physical entity that means it occupies space in a memory. It’s used to access members of the class.
e.g. Suppose “GABS” is the name of the class.
GABS G1, G2;
G1.show( );
Both G1 and G2 are the objects of the class “GABS”

Question 2:
Rewrite the following program after removing the syntactical errors (if any). Underline each correction. Delhi 2012

#include<iostream.h> 
class Book 
{
long Bld.Qty; 
public:
void Purchase()
{
cin>>BId<<Qty;
}
void Sale 
{
cout<<setw(5)<<BId<<"o1d:”<<Qty<<endl;
cout<<"New:"<<—Qty<<endl;
}
};
void main()
{
Book B;
B.Purchase();
Sale();
B.Sale();
}

Аnswers:

#include<iostream.h>
#include<iomanip.h> 
class Book
{
long Bid, Qty; 
pub!ic:
void Purchase()
{
cin>>BId>>Qty;
}
void Sale()
{
cout<<setw(5)<<BId<<"o1d:"<<Qty<<endl; 
cout<<"New:"<<--Qty<<endl;
}
};
void main()
{
Book B;
B.Purchase();
B.Sale(); 
B.Sale();
}

Question 3:
Rewrite the following program after removing the syntactical errors (if any). Underline each correction. Delhi 2012

#include<iostream.h> 
class Item 
{
long IId, Qty; 
public:
void Purchase 
{
cin>>IId>>Qty;
}
void Sale()
{
cout<<setw(5)<<IId<<”old:"<<Qty<<endl;
cout<<"New: "<<--Qty<<endl;
}
};
void main()
{
Item I;
Purchase():
I.Sale();
I.Sale();
}

Аnswers:

#include<iostream.h> 
#include<iomanip.h> 
class Item
{
long lid,Qty; 
public:
void Purchase()
{
cin>>IId>>Qty;
}
void Sale()
{
cout<<setw(5)<<IId<<"01d:"<<Qty<<endl;
cout<<"New:"<<--Qty<<endl;
}
};
void main()
{
Item I;
I.Purchase();
I.Sale();
I.Sale();
}

Question 4:
Rewrite the following program after removing the syntactical error(s) (if any). Underline each correction. Delhi 2012C

#include<iostream.h>
#include<stdio.h>
Class OFFER 
{
int OfferId; 
char Description[80]: 
void Show 
{
cout<<offerId<<" : ”<<Description<<endl;
}
public:
void Enter 
{
cin>>offerId; 
gets>>Description;
}
};
void main()
{
OFFER Obj;
Obj.Enter();
Obj.Show();
}

Аnswers:

#include<iostream.h> 
#include<stdio.h> 
class OFFER
{
int OfferId; 
char Description[80]; 
void Show()
{
cout<<offerld<<":"<<Description<<endl; 
}
public:
void Enter()
{ 
cin>>offerId; 
gets(Description):
}
};
void main()
{
OFFER Obj;
Obj.Enter();
//Obi.Show();
//Show()cannot be called because
//it is a private member
}

Question 5:
What is the difference between members in private visibility mode and the members in public visibility mode inside a class? Also give a suitable C++ code to illustrate both. Delhi 2012
or
Differentiate between public and private visibility modes in context of object oriented programming using a suitable example. Delhi 2011
Аnswers:
A member declared as private remains hidden from outside world and it can only be accessed by the member function of the class in which it is declared. A member declared as public is made available to the outside world. That is , it can be accessed by any function, any expression in the program but only by using an object of the same class type.
e.g-

class A 
{
private:
int x;
void show(); 
public: 
int y;
void get();
};

The members x and show( ) are private and these are not accessible outside the class where the members y and get( ) are public so these are accessible outside the class.

Question 6:
When is public visibility of a mode applied to members of a class? Also give an example to illustrate. Delhi 2011C
Аnswers:
When we need to access the members from out side the class then we apply public mode preceding any members.
e.g.

#include<iostream.h> 
class ABC 
{
public: 
int b; 
void show()
{
cout<<"b ="<<b;
}
};
void main()
{
ABC x; 
x.b=20; 
x.show();
}

Question 7:
Rewrite the following C++ program code after removing the syntax error(s) (if any). Underline each correction.
All India 2010

include<iostream.h>
class FLIGHT 
{
long FlightCode;
char Description[25]; 
public
void Addlnfo()
{
cin>>FlightCode; 
gets(Description);
}
void ShowInfo()
{
cout<<FlightCode«":" <<Description<<endl;
}
};
void main()
{
FLIGHT F;
Addlnfo.F();
Showlnfo.F();
}

Аnswers:

# include<iostream.h>
#include<stdio.h>
class FLIGHT 
{
long FlightCode; 
char Description[25]; 
public:
void Addlnfo()
{
cin>>FlightCode; 
gets(Descri pti on);
}
void Showlnfo()
(
cout<<FlightCode<<":"<<Description<<endl;
}
};
void main()
{
FLIGHT F;
F.Addlnfo();
F.ShowInfo();
}

Question 8:
Rewrite the following C++ program code after removing the syntax error(s) (if any). Underline each correction.
Delhi 2010

#include<iostream.h> 
class TRAIN 
{
long TrainNo;
char Description[25];
public
void Entry()
{
cin>>TrainNo; 
gets(Description);
}
void Display()
{
cout<<TrainNo<<":"<<Description<<endl;
}
};
void main( )
{
TRAIN T;
Entry. T();
Display.T();
}

Аnswers:

#include<iostream.h> 
#include<stdio.h> 
class TRAIN 
{
long TrainNo;
char Description[25];
public:
void Entry()
{
cin>>TrainNo;
gets(Description);
}
void Display()
{
cout<<TrainNo<<" : "<<Description<<endl;
}
};
void main()
{
TRAIN T;
T.Entry();
T.Display();
}

Question 9:
Rewrite the following program after removing the syntactical error(s) (if any) Underline each correction. Delhi 2009C

#include<iostream.h>
class Transport 
{
char Model[20]; 
char Name[20]; 
void Get()
{
gets(Model); 
gets(Name);
}
void Show()
{
cout<<Model<<endl; 
puts(Name);
}
};
void main( )
{
Transport T;
T.Get();
Show();
}

Аnswers:

#include<iostream.h> 
#include<stdio.h> 
class Transport 
{
char Model[20]; 
char Name[20]; 
public: 
void Get() 
{
gets(Model); 
gets(Name);
}
void Show() 
{
cout<<Model<<endl; 
puts(Name);
}
};
void main()
{
Transport T:
T.Get();
T.Show();
}

4-5 Marks Questions

Question 10:
Write the definition of a class BOX in C++ with the following description: All India 2017

Аnswer:

class Box 
{
int BoxNumber; 
float Side, Area; 
void ExecArea()
{
Area = Side*Side;
}
public:
void GetBox()
{
cout<<"Enter the values of BoxNumber and Side”; 
cin>>BoxNumber; 
cin>>Side;
ExecArea(); 
}
void ShowBox()
{
cout<<"BoxNumber:"<<BoxNumber<<endl; 
cout<<”Side:"<<Side<<endl: 
cout<<”Area:"<<Area;
}

Question 11:
Write the definition of a class METROPOLIS in C++ with following description: Delhi 2016

Аnswer:

class METROPOLIS 
{
int MCode; 
char MName[20]; 
long int MPop; 
float Area, PopDens; 
void CalDen()
{
PopDens = MPop/Area;
}
public:
void Enter()
{
cout<<"\nEnter the code";
cin>>MCode;
cout<<"\nEnter the name"; 
gets(MName);
cout<<"\n Enter the population"; 
cin>>MPop;
cout<<"\n Enter the area coverage";
cin>>Area;
CalDen();
}
void ViewALL() 
{
cout<<"\nCode: "<<MCode; 
cout<<"\nName: "<MName; 
cout<<"\nPopulation:"<<MPop; 
cout<<"\nArea Coverage : "<<Area ; 
cout<<"\nPopulation Density :"<<PopDens; 
if(PopDens>12000)cout<<"Highly Populated Area";
}
};

Question 12:
Write the definition of a class CITY in C++ with following description: All India 2016

Аnswer:

class CITY 
{
int Ccode;
char CName[20];
long int Pop; 
float KM, Density; 
void DenCal()
{
Density = Pop/KM;
}
public :
void Record()
{
cout<<"\nEnter the city code"
cin<<Ccode;
cout<<"\nEnter the city name"
gets(CName);
cout<<"\nEnter city’s populiation"
cin>>Pop;
cout<<"\nEnter the Area coverage by city";
cin>>KM;
DenCal ();
}
void View()
{
cout<<"\nCity code:"<<Ccode; 
cout<<"\nCity name:"<<CName; 
cout<<"\nPopul at ion:"<<Pop; 
cout<<"\nArea coverage:"<<KM;
cout<<"\nPopul ation density:"<<Density; 
if(Density>10000) 
cout<<"Highly Populated City"; 
}
};

Question 13:
Write the definition of a class PIC in C++ with following description Delhi 2015

Аnswer:

class PIC 
{
int Pno;
char Category[20]; 
char Location[20]; 
void FixLocation()
{
if(strcmp(Category,"Antique”)==0) 
strcpy(Location,"Ustad Khan"); 
else if(strcmp(Category,"Modern" )==0)
strcpy(Location,"Jim Plaq”); 
else if(strcmp(Category,”Classic”)==0) 
strcpy(Location,"Amina");
}
public:
void Enter() 
{
cout<<"\nEnter the picture number";
cin>>Pno;
cout<<"\nEnter the category"; gets(Category);
FixLocation(); 
}
void SeeAll() 
{
cout<<"\nPicture number:"<<Pno; 
cout<<"\nCategory: "<<Category; 
cout<<"\nLocation:"<<Location; 
}
};

Question 14:
Write the definition of a class Photo in C++ with following description: All Indio 2015

Аnswer:

class Photo 
{
int Pno;
char Category[20]; 
char Exhibit[20]; 
void FixExhibit()
{ 
if(strcmp(Category,"Antique")== 0) 
strcpy(Exhibit, "Zaveri"); 
else if(strcmp(Category,"Modem") == 0) 
strcpy(Exhibit, "Johnsen"); 
else if(strcmp(Category,"Classic") == 0) 
strcpy(Exhibit, "Terenida”);
}
public:
void Register()
{
cout<<"\nEnter the photo number";
cin>>Pno;
cout<<"\nEnter the category"; 
gets(Category);
FixExhibit();
}
void ViewAll()
{
cout<<"\nPhoto number :"<<Pno; 
cout<<"\nCategory:"<<Category; 
cout<<"\nExhibit:”<<Exhibit;
}
};

Question 15:
Write the definition of a class STAFF in C++ with following description: All India 20isc

Public Members

• Enroll( )  //A function to allow user to enter values
  //SID, Type, Name and call
  //AssignPay( ) function
• SeeData( ) //A function to display all the data members

Аnswer:

class STAFF 
{
long int SID; 
char Type; 
float Pay; 
char Name[30]; 
void AssignPay()
{
if(Type == 'D')
Pay = 95000; 
else if(Type == 'M')
Pay = 75000; 
else if (Type == 'E')
Pay = 60000; 
else if(Type == 'S')
Pay = 45000;
}
public:
void Enroll()
{
cout<<”Enter the values of staff ID, Type, Name"; 
cin>>SID; 
cin>>Type; 
gets(Name);
AssignPay();
}
void seeData()
{
cout<<SID<<Type<<Name<<Pay;
}
};

Question 16:
Define a class Seminar with the following specification private members: Delhi 2013C
Seminarld long
Topic string of 20 characters
VenueLocation string of 20 characters
Fee float
CalcFee( ) function to calculate Fee depending on VenueLocation

Venue Location	Fee
Outdoor	5000
Indoor Non-AC	6500
Indoor AC	7500

Public members
Register( ) function to accept values for Seminarld, Topic, VenueLocation and call CalcFee( ) to calculate Fee.
ViewSeminarf( ) function to display all the data members on the screen.

Аnswer:

class Seminar 
{
long SeminarId;
char Topic[20]. VenueLocation[20]; 
float Fee; 
void CalcFee()
{
if(strcmp(VenueFocation,"Outdoor")==0)
Fee=5000;
else if(strcmp(Venuetocation,"Indoor Non-AC")==0) 
Fee=6500;
else if(strcmp(VenueFocation,"Indoor AC")==0)
Fee=7500;
}
public:
void Register()
{
cout<<"Enter Seminar Id"; 
cin>>SeminarId; 
cout<<"Enter Topic"; 
gets(Topic);
cout<<"Enter Venue Focation";
gets(VenueLocation);
CalcFee(); 
}
void ViewSeminar()
{ 
cout<<"SeminarId:"<<SeminarId<<endl; 
cout<<"Topic: "<<Topic<<endl; 
cout<<"Venue Location;"<<VenueFocation<<endl; 
cout<<"Fee is:"<<Fee;
}
};

Question 17:
Define a class RESTRA in C++ with following description: Delhi 2012
Private members

• FoodCode of type int
• Food of type string
• FType of type string
• Sticker of type string
• A member function GetStickerf( ) to assign the following values for Food Sticker as per the given FType

FType Sticker
Vegetarian GREEN
Contains Egg YELLOW
Non-Vegetarian RED

Public members

• A function GetFood( ) to allow user to enter values for FoodCode, Food, FType and call function GetSticker( ) to assign Sticker.
• A function ShowFoodf( ) to allow user to view the content of all the data members.

Аnswer:

class RESTRA 
{
int FoodCode;
char Food[30], FType[20],Sticker[20];
void GetSticker()
{
if(strcmp(FType,"Vegetari an”)==0) 
strcpy(Sticker,"GREEN"); 
else if(strcmp(FType,"Contains Egg")==0)
strcpy(Sticker,"YELLOW"); 
else if(strcmpCFType,"Non-Vegetarian")==0) 
strcpy(Sticker,"RED”); 
}
public:
void GetFood() 
{
cout<<"Enter FoodCode, Food, Food Type";
cin>>FoodCode; 
gets(Food); 
gets(FType);
GetSticker();
}
void ShowFood()
{ 
cout<<"Entered values of FoodCode, Food, FoodType,Sticker";
cout<<FoodCode<<Food<<FType<<Sticker;
}
};

Question 18:
Define a class SUPPLY in C++ with following description: All Indio 2012
Private members

• Code of type int
• FoodName of type string
• Sticker of type string
• FoodType of type string
• A member function GetTypef ( ) to assign the following values for FoodType as per the given Sticker

Sticker  FoodType
GREEN  Vegetarian
YELLOW  Contains Egg
RED  Non-Vegetarian
Public members

• A function FoodIn( ) to allow user to enter values for Code, FoodName, Sticker and call function GetType( ) to assign respective FoodType.
• A function FoodOut( ) to allow user to view the content of all the data members.

Аnswer:

class SUPPLY 
{
int Code;
char FoodName[30],Sticker[30]; 
char FoodType[20]; 
void GetType()
{
if(strcmp(Sticker, "GREEN”)==0) 
strcpy(FoodType,"Vegetarian" ); 
else if(strcmp(Sticker,"YELLOW")==0) 
strcpy(FoodType,"Contains Egg"); 
else if(strcmp(Sticker,"RED")==0) 
strcpy(FoodType,"Non -Vegeta rian"); 
}
public:
void FoodIn()
{
cout<<"Enter Code, FoodName, Sticker";
cin>>Code;
gets(FoodName); 
gets(Sticker);
GetType(); 
}
void Food0ut()
{
cout<<"Code,FoodName,Sticker,FoodType are"; 
cout<<Code<<FoodName<<Sticker<<FoodType;
}
};

Question 19:
Define a class Candidate in C++with following description: Delhi 2o11
Private members

• A data member RNo (Registration Number) of type long
• A data member Name of type string
• A data member Score of type float
• A data member Remarks of type string
• A member function AssignRem( ) to assign the remarks as per the score obtained by a candidate.
• Score range and the respective remarks are shown as follow:

Score Remarks
>=50  Selected
less than 50  Not Selected
Public members

• A function ENTER( ) to .allow user to enter values for RNo, Name, .Score and call function AssignRem( ) to assign Remarks.
• A function DISPLAY( ) to allow user to view the content of all data members.

Аnswer:

class Candidate 
{
long RNo; 
char Name[40]; 
float Score; 
char Remarks[20]; 
void AssignRem()
{
if(Score>=50)
strcpy(Remarks,"Selected"); 
else
strcpy(Remarks,"Not Selected");
}
public: 
void ENTER()
{
cout<<"Enter the values for Rno,Name,Score”;
cin>>RNo; 
gets(Name); 
cin>>Score;
AssignRem(); 
}
void DISPLAY()
{
cout<<RNo<<Name<<Score<<Remarks; 
}
};

Question 20:
Define a class Applicant in C++ with following description: All IndiA 2011
Private members

• A data member ANo (Admission Number) of type long
• A data member Name of type string
• A data member Agg (Aggregate Marks) of type float
• A data member Grade of type char
• A member function GradeMe( ) to find the grade as per the aggregate marks obtained by a student. Equivalent aggregate marks range and the respective grades are shown as follow:

Aggregate marks  Grade
>=80 A
less than 80 and >=65 B
less than 65 and >=50 C
less than 50 D
Public members

• A function ENTER( ) to allow user to enter values for ANo, Name, Agg and call function GradeMe( ) to find the Grade.
• A function RESULT( ) to allow user to view the content of all data members.

Аnswer:

class Applicant
{
long ANo; 
char Name[40]; 
float Agg; 
char Grade; 
void GradeMe()
{
if(Agg>=80) 
Grade='A';
else if(Agg<80 && Agg>=65) 
Grade='B';
else if(Agg<65 && Agg>=50) 
Grade='C'; 
else
Grade='D';
public: 
void ENTER()
{
cout<<"Enter the values for Ano.Name.Agg"
cin>>ANo; 
gets(Name); 
cin>>Agg;
GradeMe();
}
void RESULT()
{
cout<<ANo<<Name<<Agg<<Grade;
}
};

Question 21:
Define a class ITEM in C++ with the following specification: Delhi 2010
Private members

• Code of type integer (Item Code)
• Iname of type string (Item Name)
• Price of type float(Price of each item)
• Qty of type integer(Quantity of item stock)
• Offer of type float(Offer percentage on the item)
• A member function GetOffer( ) to calculate offer percentage as follows:

If Qty <=50 Offer is 0
If 50<Qtv<=l 00 Offer is 5
If Qty >100 Offer is 10
Public members

• A function GetStock( ) to allow user to enter values for Code, Iname, Price, Qty and call function GetOffer( ) to calculate offer.
• A function ShowItem( ) to allow user to view the content of all data members.

Аnswer:

class ITEM
{
int Code;
char Iname[20]: 
float Price; 
int Qty; 
float Offer; 
void GetOffer()
{
if(Qty<=50) 
Offer=0;
else if(Qty<=100) 
Offer=5; 
else
Offer=10;
}
public:
void GetStock()
{
cout<<"Enter the values for code, Item name, Price, Quantity";
cin>>Code; 
gets(Iname); 
cin>>Price>>Qty;
GetOffer();
}
void ShowItem()
{
cout<<Code<<Iname<<Price<<Qty<<Offer;
}
};

Question 22:
Define a class STOCK in C++ with the following specification: All India 2010
Private members

• ICode of type integer (Item Code)
• Item of type string (Item Name)
• Price of type float(Price of each item)
• Qty of type integer(Quantity in stock)
• Discount of type float(Discount percentage on the item)
• A member function FindDisc( ) to calculate discount percentage as follows:

If Qty <=50 Discount is 0
If 50<Qty<=100 Discount is 5
If Qty >100 Discount is 10 Public members

• A function Buy( ) to allow user to enter values for ICode, Item, Price, Qty and call function FindDisc( ) to calculate discount.
• A function ShowAll( ) to allow user to view the content of all data members.

Аnswer:

class STOCK 
{
int ICode; 
char Item[20]: 
float Price: 
int Qty; 
float Discount: 
void FindDisc():
{
if(Qty<=50)
Discount=0; 
else if(Qty<=100) 
Discount=5; 
else
Discount=10;
}
public: 
void Buy()
{
cout<<"Enter the values for Icode,Item,Price,Qty"; 
cin>>ICode; 
gets(Item); 
cin>>Price>>Qty;
FindDisc();
}
void ShowAll()
{
cout<<ICode<<Item<<Price<<Qty<<Discount;
}
};

Question 23:
Define a class RESORT in C++ with the following specification: Delhi 2009
Private members

• Rno – Data member to store room number
• Name – Data member to store customer name
• Charges – Data member to store per day charges
• Days – Data member to store number of days of stay
• COMPUTEO – Function to calculate and return amount as days*charges and if the value of days *charges is more than 11000, then as 1.02*Days *Charges

Public members

• Getinfo( ) Function tfo enter the content Rno, Name, Charges and Days
• Dispinfo( ) Function to display Rno, Name, Charges, Days and Amount (amount to be displayed by calling function COMPUTE( ))

Аnswer:

class RESORT 
{
int Rno; 
char Name[30]; 
float Charges; 
int Days ; 
float COMPUTE()
{
float temp=Days*Charges; 
if(temp>11000) 
return(1.02*temp);
return temp; 
}
public:
void Getinfo()
{
cout<<"enter the room number:"; 
cin>>Rno;
cout<<"enter the customer name:"; 
gets(Name);
cout<<”enter the room charges per day";
cin>>Charges;
cout<<"enter number of days stayed by customer:"; 
cin>>Days:
}
void Dispinfo()
{
cout<<"Room number:"<<Rno; 
cout<<"Customer Name:"; 
puts(Name) ;
cout<<"Charges per day:"<<Charges; 
cout<<"Number of days stayed by customer:"<<Days; 
cout<<"Total charges of customer: "<<COMPUTE();
}
};

Question 24:
Define a class HOTEL in C++ with the following specification: All IndiA 2009
Private members

• Rno Data member to store room number
• Name Data member to store customer name
• Tariff Data member to store per day charges
• NOD Data member to store number of days of stay
• CALC( ) Function to calculate and return amount as NOD*Tariff and if the value of NOD*Tariff is more than 10000, then as 1.05 NOD *charges

Public members

• Checkin( ) Function to enter the content Rno, Name, Tariff and NOD
• Checkout( ) Function to display Rno, Name, Tariff, NOD and Amount (amount to be displayed by calling function
  CALC( ))

Аnswer:

class HOTEL 
{
int Rno,NOD; 
char Name[30]; 
float Tariff; 
float CALC()
{
float temp=NOD*Tariff; 
if(temp>10000) 
return(1.05*temp); 
return temp;
} 
public:
void Checkin()
{
cout«"Enter the room number:";
cin>>Rno;
cout<<"Enter the customer name:";
gets(Name);
cout<<"Enter the room charges per day";
cin>>Tariff ;
cout<<"Enter number of days stayed by customer:"; 
cin>>NOD;
}
void Checkout()
{
cout<<"Room number:"<<Rno; 
cout<<"Customer Name:"; 
puts(Name); 
cout<<"Charges per day:"<<Tariff; 
cout<<"Number of days stayed by customer:"<<NOD; 
cout<<"Total charges of customer:"<<CALC();
}
};