This document discusses various C++ concepts like pointers, polymorphism, streams, and input/output operations. It defines pointers as variables that hold memory addresses and explains pointer syntax. It describes compile-time and run-time polymorphism, virtual functions, and pure virtual functions. It also outlines the stream classes like cin and cout for input and output, and discusses formatted and unformatted input/output operations using manipulators and functions.

1. R.KARTHIKEYAN
Assistant Professor
Department of Commerce(CA)
Vivekananda College
Tiruvedakam West
Madurai – 625 234
E-mail : vishalkarthi12@gmail.com
Contact No: 97893 89135

3.  Pointers
 Polymorphism
 Polymorphism Types
 This Pointer
 Virtual Functions
 Pure Virtual Function
 C++ Stream
 Stream Classes
 Unformatted I/O operations
 Formatted I/O operations
.

4. Pointers
 Pointer is a variable, that holds the address of
another variable.
 Every variable is a memory location and every
memory location has its address defined which can
be accessed using ampersand (&) operator which
denotes an address in memory.
 Like any variable or constant, you must declare a
pointer before you can work with it.

5. Syntax of Pointer variable declaration
type *var-name;
 type is the pointer's base type
 var-name is the name of the pointer variable.
int *ip; // pointer to an integer
float *fp; // pointer to a float
Note: Asterisk is being used to designate a variable as
a pointer.

6. Example
#include <iostream>
#include <conio.h>
int main ()
{
int var = 20;
int *ip;
ip = &var;
cout << "Value of var variable: ";
cout << var << endl;
cout << "Address stored in ip variable: ";
cout << ip << endl;
cout << "Value of *ip variable: ";
cout << *ip << endl;
return 0;
}
Output:
Value of var variable: 20
Address stored in ip variable:
0x7ffc787f0f44
Value of *ip variable: 20

7. Polymorphism
 Polymorphism means having many forms.
 polymorphism means that a call to a
member function will cause a different
function to be executed depending on the
type of object that invokes the function.

8. Types of Polymorphism

9. COMPILE TIME POLYMORPHISM.
 Static Polymorphism also known as
compile time polymorphism.
 Polymorphism that is resolved during
compiler time is known as static
polymorphism.
 Method overloading is an example of
compile time polymorphism.
Method overloading:
Method Overloading is more than one method having the
same name, if their argument lists are different.

10. Run Time Polymorphism
 Dynamic Polymorphism also known as
runtime polymorphism.
 Dynamic polymorphism is a process in which
a call to an overridden method is resolved at
runtime, thats why it is called runtime
polymorphism.

11. Virtual Function
 A virtual function is a member function in
the base class that you redefine in a derived
class.
 A 'virtual' is a keyword preceding the normal
declaration of a function.
Syntax:
virtual return _type f unction name()
{
}

12. Base Class
Derived Class
Member Function

13. Pure Virtual Function
 Pure Virtual function are virtual functions with
no definition.
 They start with Virtual keyword and ends with =
0.
Virtual void display () = 0
class Test
{
// Data members of class
public:
virtual void show() = 0;
/* Other members */
};
Pure Virtual Function

14. This pointer
 This pointer is used to represent the
address of an object inside a member
function.
 The this pointer is an implicit parameter to
all member functions.
 Friend functions do not have a this pointer,
because friends are not members of a class.
 Only member functions have a this pointer.

15. This pointer Example
class Test
{
private:
int x;
public:
void setX (int x)
{
this->x = x;
}
void print()
{
cout << "x = " << x << endl;
}
};
int main()
{
Test obj;
int x = 20;
obj.setX(x);
obj.print();
return 0;
}

16. Streams
A transfer of information in the form of sequence of bytes.
The I/O system of c++ contains:
 Istream class supports Input function
 Ostream class supports Output function
 iostream standard library, which provides cin and cout methods
for reading from standard input and writing to standard output.

17. Stream Classes

19. Cin
 Cin is predefined object of istream
class.
 The cin object is attached to be
standard input device.
 Cin is used in Conjuction with stream
extraction operator, which is written
as >>.

20. #include <iostream.h>
#include <conio.h>
int main()
{
int no;
cout<<"Enter a number ";
cin>>no;
cout<<"Number entered is ="<<no;
return 0;
}
Output:
Enter a number 55
Number entered is = 55

21. Cout
 Cout is predefined object ofostream
class.
 The cout object is to be connected to
the standard output device, which
display in screen.
 Cout object connected with stream
insertion operator as <<.

22. Cout
include <iostream>
include <iostream>
int main()
{
int a=10;
Cout<<“Value of the a:”<<a<<endl;
}
Output:
Value of the a:10

23. Formatted I/O Operations
Format the I/O operations like determining the
number of digits to be displayed after the decimal
point, specifying number base .
 Using the ios class or various ios member functions.
 Using manipulators(special functions)

24. ios class functions
width(): The width method is used to set the required
field width. The output will be displayed in the given
width.
precision(): The precision method is used to set the
number of the decimal point to a float value.
fill(): The fill method is used to set a character to fill in
the blank space of a field.
setf(): The setf method is used to set various flags for
formatting output.
unsetf(): The unsetf method is used To remove the
flag setting.

25. Manipulators
 Manipulators are operators used in C++ for formatting
output.
 The data is manipulated by the programmer’s choice of
display.
Endl
This manipulator has the same functionality as the ‘n’
newline character.
Example:
cout << “exam" << endl;
setw
This manipulator sets the minimum field width on output.

26. Manipulators
Setfill
 This is used after setw manipulator.
 If a value does not entirely fill a field, then the character
specified in the setfill argument of the manipulator is used
for filling the fields.

27. Manipulators
setprecision :
 The setprecision Manipulator is used with floating point
numbers.
 It is used to set the number of digits printed to the right of the
decimal point.
Example:
#include <iostream>
#include <iomanip>
void main( )
{
float x = 0.1;
cout << fixed << setprecision(3) << x << endl;

28. Unformatted consol input output
Unformatted console input/output functions are used to read a
single input from the user at console and it also allows us to
display the value in the output to the user at the console.
get () – used to read a single character from the i/p device.
Syntax:
char c=cin.get();
put() – used to print a single character on to the console.
Syntax:
cout.put(variable / character);

29. getline() - reads array of characters that ends with ‘n’
by default or until the limit is reached.
#include<iostream>
#include<conio.h>
int main()
{
cout<<"Enter name :";
char c[10];
cin.getline(c,10);
cout<<c<<endl;
return 0;
}
It takes 10 characters as input;

30. write() – print the array of characters to the console
#include<iostream>
#include<conio.h>
int main()
{ cout<<"Enter name : ";
char c[10]; cin.getline(c,10);
cout.write(c,9);
return 0;
}
It takes 10 characters as input;