What is function? What is call by value? What is call by reference? What is the difference between them?

What is function? What is call by value? What is call by reference? What is the difference between them?
by

1 Answer

Answer :

Function:

A function is a group/set of statements/instruction that performs a specific task. It can be system defined i.e. clrscr(), getch(), or user defined i.e. add(), sub().


Call by Value:

In call by value, original value is not modified.

In call by value, value being passed to the function is locally stored by the function parameter in stack memory location. If you change the value of function parameter, it is changed for the current function only. It will not change the value of variable inside the caller method such as main().


Call by Reference:

In call by reference, original value is modified because we pass reference (address).

Here, address of the value is passed in the function, so actual and formal arguments share the same address space. Hence, value changed inside the function, is reflected inside as well as outside the function.

Difference between Call by Value and Call by Reference:

image

by

Related questions

Differentiate between call by value and call by reference method.

Description : Differentiate between call by value and call by reference method.

Last Answer : Call by Value Call by reference In call by value, a copy of actual arguments is passed to respective formal arguments. In call by reference, the location, that is, the address of actual arguments is ... ;a,&b); //function call void swap(int *a,int *b)// function definition { }

Explain object as a function argument using following points with suitable example: (i) Pass by value (ii) Pass by reference

Description : Explain object as a function argument using following points with suitable example: (i) Pass by value (ii) Pass by reference

Last Answer : (i) Pass by Value: When an object is passed by value to a function, a copy of that object is created and changes are reflected on the copy object not on original object. Example: #include #include class Example { int x; public: Example(int a)  {  x=a;  }  void print()  { cout

Write a program to swap two integer values by using call by reference.

Description : Write a program to swap two integer values by using call by reference.

Last Answer : #include #include void swap(int *a,int *b) { int c; c=*a; *a=*b; *b=c; } void main() { int a,b; couta; coutb; cout

What is multiple inheritance? What is multilevel inheritance? What is difference between them?

Description : What is multiple inheritance? What is multilevel inheritance? What is difference between them?

Last Answer : Multiple Inheritance: When A derived class is derived from more than one base class then it is known as multiple inheritance. A derived class can inherit the attributes of all base classes ... , last derived class will inherit only public property of all class including intermediate class.

How to define virtual function? Give example.

Description : How to define virtual function? Give example.

Last Answer : A virtual function is a member function that is declared within a base class and redefined by a derived class. To define virtual function following syntax is used: Class baseclass { virtual function_name() { } ... } }; Example: #include class Base { public: virtual void show( ) { cout

Explain how to pass object as function argument.

Description : Explain how to pass object as function argument.

Last Answer : An object may be used as function arguments in two methods:- i) A copy of the entire object is passed to the function. ii) Only the address of the object is transferred to the function. 1) Pass-by-value Since a copy ... (int h, int m) { hours = h; minutes = m; } void puttime(void)  { cout

Explain the need of static member function with example.

Description : Explain the need of static member function with example.

Last Answer : A static member function can have access to only other static members (functions or variables) declared in the same class. A static member function can be called using the class name as follows: class_name:: ... test::showcount(); -------------Call to static member function. }

What is pure virtual functions? Write down the rules used for pure virtual function.

Description : What is pure virtual functions? Write down the rules used for pure virtual function.

Last Answer : A pure virtual function is a function which is declared in a base class and which does not have definition relative to the base class. In such cases, the compiler requires each derived class to either ... A class containing pure virtual functions cannot be used to declare any objects of its own.  

Write a program to show object as function argument.

Description : Write a program to show object as function argument. 

Last Answer : #include<iostream.h> #include<conio.h> #include<string.h> class objarg  { char str[10]; public: void get() { cout<<"\n Enter a Message"; cin>>str; } void ... clrscr(); o1.get(); o2.copy(o1); o2.display(); getch();  }

What is the need of virtual function? Explain with example.

Description : What is the need of virtual function? Explain with example.

Last Answer : When base class and its derived class both contain same name and prototype member function then derived class function overrides base class function. Base class pointer is used to refer member functions of its ... Program/Example: #include class Base { public: virtual void show( ) { cout

Polymorphism is implemented using function overloading. Justify the statement.

Description : Polymorphism is implemented using function overloading. Justify the statement.

Last Answer : Polymorphism is a mechanism that allows a developer to have more than one function with same name but different signature. In function overloading, one can make use of more than one function with different signature as well. Hence ... main()  { int a[10],i,isum; float b[5],fsum; clrscr(); cout

Why friend function is required? Give four characteristics of friend function.

Description : Why friend function is required? Give four characteristics of friend function.

Last Answer : Friend function: Private members of a class cannot be accessed from outside the class. A non-member function cannot have an access to the private data of a class. Sometimes, two classes may need to ... part of a class without affecting its meaning. 6. Usually it has the objects as the arguments.

Explain concept of function overriding with example.

Description : Explain concept of function overriding with example.

Last Answer : Function Overriding:- When derived class defines same name function, as defined in its base class then it is called as function overriding. In this a function in the derived class overrides the inherited function. Example : #include #include class Base { public: void Display() { cout

How do we invoke a constructor function?

Description : How do we invoke a constructor function?

Last Answer : A constructor is invoked automatically when an object of its class is created. Example: class ABC { public: ABC( ) { } }; void main( ) { ABC obj; } In the above example, creating „obj‟ object automatically invokes constructor ‟ABC ( )‟.

Write a program to calculate area of circle and area of rectangle using function overloading.

Description : Write a program to calculate area of circle and area of rectangle using function overloading. 

Last Answer : #include<iostream.h> #include<conio.h> float area(float a) { return (3.14*a*a); } int area(int p,int q) { return(p*q); } void main() { clrscr(); cout< ... ;<<area(6); cout<<"Area of Rectangle:"<<area(5,6); getch(); }

List characteristics of static data member and static member function.

Description : List characteristics of static data member and static member function.

Last Answer : Characteristics of static member variable are: i) It is initialized to zero when the first object of its class is created. No other initialization is permitted. ii) Only one copy of that ... the class name with a scope resolution operator instead of object name as follows: class_name::function_name;

Differentiate between function definition inside and outside the class

Description : Differentiate between function definition inside and outside the class

Last Answer : Sr. No Inside function definition Outside function definition  1 A member function of a class is defined inside the class. A member function of a class is declared inside class and as defined outside the ... }; void item :: getdata(int a, float b) { number = a; cost = b; }

Write a program to demonstrate the use of pure virtual function.

Description : Write a program to demonstrate the use of pure virtual function.

Last Answer : Consider the following example where parent class provides an interface to the base class to implement a function called getArea() as pure virtual function: #include // Base class class Shape { protected: int ... ; Rect.setWidth(5); Rect.setHeight(7); // Print the area of the object. cout

Explain static member function.

Description : Explain static member function.

Last Answer : Static member function: - a static member function can have access to only other static variables or functions declared in the same class. It can be called using the class name instead of its object. It can be declared ... ; } static void showcount()----------------static member function { cout

Explain friend function. Give example.

Description : Explain friend function. Give example.

Last Answer : Friend function: The private members of a class cannot be accessed from outside the class but in some situations two classes may need access of each other s private data. So a common function can be declared which can be made friend of ... xyz x1; a1.get1(); x1.get1(); add(a1,x1); }

Explain the concept of virtual function with example.

Description : Explain the concept of virtual function with example.

Last Answer : Virtual Function: A virtual function is a member function that is declared within a base class and redefined by its derived class. When base class and its derived class both contain same name member function then ... pointer. Example: #include class Base { public: virtual void show( ) { cout

How to define a member function outside the body of class?

Description : How to define a member function outside the body of class? 

Last Answer : The user can declare member function outside the class with the help of scope resolution operator (::). The label class_name:: tells the compiler that the function_name belongs to the class class_name. ... In above example accept() member function of class student is defined outside of the class. 

Write a program in C++ to overload a „volume‟ function to calculate volume of cube and rectangular box.

Description : Write a program in C++ to overload a „volume‟ function to calculate volume of cube and rectangular box. 

Last Answer : #include<iostream.h> #include<conio.h> void volume(float); void volume(float, float, float); void main() { float a, length, width, height; clrscr(); cout<<"\n ... width*height; cout<<"\n Volume of a rectangular box is:"<<v; }

State any four characteristics of friend function.

Description : State any four characteristics of friend function.

Last Answer : Characteristics of friend function: 1. It is not in the scope of the class to which it has been declared as friend. 2. As it is not in the scope of the class, it cannot be called using the ... public or the private part of a class without affecting its meaning. 6. It has the objects as arguments.

Describe syntax and use of defining member function outside class. Give one example.

Description : Describe syntax and use of defining member function outside class. Give one example.

Last Answer : Member function that is declared inside a class has to be defined separately outside the class. These member functions associate a membership identify label in the header. This label tells the ... ) A member function can call another member function directly, without using the dot operator. 

Write a program in C++ to declare a class measure having data members as add 1, add 2, add 3. Initialize the values of two data members using constructor and display their addition using function.

Description : Write a program in C++ to declare a class measure having data members as add 1, add 2, add 3. Initialize the values of two data members using constructor and display their addition using function.

Last Answer : #include<iostream.h> #include<conio.h> class measure { public: int add1,add2,add3; measure(int a,int b) { add1=a; add2=b; } void cal() { add3=add1+add2; } void display() ... ;>a>>b; measure m1(a, b); m1.cal(); m1.display(); getch(); }

With example, describe use of static member function.

Description : With example, describe use of static member function.

Last Answer : A static member function can have access to only other static members (functions or variables) declared in the same class. A static member function can be called using the class name as follows: class_name:: ... static void showcount()----------------//static member function { cout

With suitable example, describe use of virtual function in polymorphism.

Description : With suitable example, describe use of virtual function in polymorphism.

Last Answer : In order to achieve polymorphism, objects belonging to different classes should be able to respond to the same message at different instances which initiates the use of single pointer variable to refer to objects of ... void accept() { coutroll; coutname; } virtual void display() { cout

Use the concept of operator overloading to overload unary ‘-‘ operator to negate value of variables.

Description : Use the concept of operator overloading to overload unary ‘-‘ operator to negate value of variables.

Last Answer : # include <iostream.h> #include<conio.h> class unary { int x, y, z; public: void getdata (int a, int , int c); void display (void); void operator - (); // overload unary minus. }; ... u. display ( ) ; -u; cout<< " u : " ; u. display ( ) ; }

What is polymorphism? Enlist different types of polymorphism. What are the differences between them?

Description : What is polymorphism? Enlist different types of polymorphism. What are the differences between them?

Last Answer : Polymorphism: It is a feature of object oriented programming which allows a programmer to have a more than one function having same name but different /same parameters but performs different/ ... Compile Time polymorphism o Virtual Function Difference between Types of Polymorphism:

Write a program which concate and reverse string by using pointer to string.

Description : Write a program which concate and reverse string by using pointer to string.

Last Answer : #include #include void main()  { char str1[20], str2[20], rev[20],*p1,*p2; int cnt=0; clrscr(); coutstr2;  p1=&str1[0];  p2=&str2[0]; while(*p1!='\0')  { p1++;  } while(*p2!='\0')  { *p1=*p2; p1++; p2++;  }  *p1='\0'; cout

What is constructor? How user can declared constructor in derived class? Explain with example.

Description : What is constructor? How user can declared constructor in derived class? Explain with example.

Last Answer : Constructor:- Constructor is a special member function which has same name as a class name and is used to initialize object during compile time of program. Declaring constructor in derived class If a base class contains a ... derived d(2,5); d.displaybase(); d.display(); getch(); }

Write a program which perform arithmetic operation using pointer.

Description : Write a program which perform arithmetic operation using pointer.

Last Answer : #include<iostream.h> #include<conio.h> void main() { int num[5]={56,75,22,18,90}; int ptr; int i; cout<< array elements are:: ; for(i=0;i<5;i++) ptr=num; cout<< ... 3; cout<< value of ptr+=3:: <<*ptr; cout<< \n ; getch(); }

What is structure? How user declare structure? Give example.

Description : What is structure? How user declare structure? Give example.

Last Answer : Structure is a collection of different data types written under a common name. It is a user defined data type. To Define a structure following Syntax is use:- struct structure_name { data_type variable 1; data_type ... () {  Person p1; cout>p1.name; cout> p1.age; cout> p1.salary; cout

What is copy constructor? Explain with example.

Description : What is copy constructor? Explain with example.

Last Answer : Copy constructor: The copy constructor is a constructor which creates an object by initializing it with an object of the same class, which has been created previously. The copy constructor is used to: ... ; // Copy constructor is called here // Let us access values assigned by constructors cout

Explain the derived class access by pointer.

Description : Explain the derived class access by pointer.

Last Answer : When base class and its derived class both contains same function name then the function in base class is declared as virtual using keyword virtual preceding its normal declaration. When a function is made virtual, C ... . Example: #include class Base { public: virtual void show( ) { cout

Write a program which implement the concept of overloaded constructor.

Description : Write a program which implement the concept of overloaded constructor.

Last Answer : #include #include class integer { int m,n; public: integer() { m=0; n=0; } //default constructor 1 integer(int a, int b) { m=a; n=b; } //Parameterized constructor 2 integer(integer &i) { m=i.m; n=i.n; } //copy constructor 3 }; void display() { cout

Explain different operator used in C++.

Description : Explain different operator used in C++.

Last Answer : :: Scope resolution operator: This operator allows access to the global version of a variable. Scope resolution operator is also used in classes to identify the class to which a member function belongs. :: ... and assigns it to the variable on its right. It is used with cin statement to input data.

Write down characteristics of object oriented programming.

Description : Write down characteristics of object oriented programming.

Last Answer : Characteristics of object oriented programming are: Emphasis is on data rather than procedure. Programs are divided into objects. Data structures are designed such that they characterize the ... can be easily added whenever necessary. Follows bottom-up approach in program designing. 

What is base class? What is derived class? Give example.

Description : What is base class? What is derived class? Give example.

Last Answer : Base class: In inheritance a new class is derived from an old class. The old/existing class is referred as base class whose properties can be inherited by its derived class. Derived class: In inheritance a new ... as well as base class. Example: class base { public: void putb() { cout

What is destructor? How destructor is declared? When destructor is invoked?

Description : What is destructor? How destructor is declared? When destructor is invoked?

Last Answer : Destructor: A destructor is a special member function used to destroy the objects that are created by a constructor. Declaration: Destructor is declared in public section of a class. It is member function ... from the program (or block or function) to clean up storage that is no longer accessible. 

What is parametrized constructor? Explain with example.

Description : What is parametrized constructor? Explain with example.

Last Answer : A constructor that can take arguments is known as parameterized constructor. In some applications, it may be necessary to initialize the various data members of different objects with different values when they ... object is created. Member function put displays the value of data member m . 

What do you mean by overloaded constructor?

Description : What do you mean by overloaded constructor?

Last Answer : When more than one constructor function is defined in a class, it is referred as overloaded constructor. Each overloaded constructor function is invoked with respect to arguments pass in the function call.

Write a program to find whether the string is palindrome or not.

Description : Write a program to find whether the string is palindrome or not.

Last Answer : #include #include #include void main() { char str1[10],str2[10]; int c; clrscr(); coutstr1; strcpy(str2,str1); strrev(str2); cout

Write a program for multiple inheritance.

Description : Write a program for multiple inheritance. 

Last Answer : #include #include class base1 { public: void show1() { cout

Give four differences between object oriented programming and procedure oriented programming.

Description : Give four differences between object oriented programming and procedure oriented programming.

Last Answer : Give four differences between object oriented programming and procedure oriented programming.

State characteristic of static data member. Explain why static data member must be defined outside the class.

Description : State characteristic of static data member. Explain why static data member must be defined outside the class. 

Last Answer : Characteristics of static data members: 1. It is initialized to zero when the first object of its class is created. No other initialization is permitted. 2. Only one copy of that member is created ... member(s) it is necessary to make static members global and re-declared outside of the class.

Explain the following with syntactic rules: (i) public inheritance (ii) protected inheritance.

Description : Explain the following with syntactic rules: (i) public inheritance (ii) protected inheritance.

Last Answer : (i) public inheritance: i) When the visibility-mode is public the base class is publicly inherited. ii) In public inheritance, the public members of the base class become public members of the derived class and ... variables; Member function; }; class B : protected A { Members of class B };

Explain the concept of memory allocation for object.

Description : Explain the concept of memory allocation for object.

Last Answer : The memory space for object is allocated when it is declared & not when the class is specified. The member functions are created & placed in memory space only once when they are defined as a ... (object 1, object 2, object 3) has its own separate memory space for its member variables.

Give the syntax and use of following with respect to (i) get() (ii) put().

Description : Give the syntax and use of following with respect to (i) get() (ii) put().

Last Answer : (i) get() function: The get() function is member of istream class. It is used to read a single character from the keyboard. Syntax of get() function: get(variable_name); example:  char c; ... /variable_name); example: cout.put( X ); The above example displays character X on the screen.