c++ theory
TRANSCRIPT
C++ Theory
Object Oriented
Programming
language
C++ is an extension to C Programming language. It was developed at AT&T BellLaboratories in the early 1980s by Bjarne Stroustrup. It is a deviation from traditionalprocedural languages in the sense that it follows object oriented programming (OOP)
approach which is quite suitable for managing large and complex programs.
Some history about of c++
Inheritance Polymorphism Encapsulation
Oop Concepts. . .
The capability of one class to inherit properties from another class as a child inherits some properties from his/her parents.The most important advantage of inheritance is code reusability. Once a base class is written and debugged, it can be used in various situations without having to redefine it or rewrite it. Reusing existing code saves time, money and efforts of writing the code again. Without redefining the old class, you can add new properties to desired class and redefine an inherited class member function.
inheritance
inheritance
vehicle
2 wheeler 4 wheeler
honda Yamaha tata mahindra
Encapsulation is the most basic concept of OOP. It is the way of combining both data and the functions that operate on that data under a single unit. The only way to access the data is provided by the functions (that are combined along with the data). These functions are considered as member functions in C++. It is not possible to access the data directly. If you want to reach the data item in an object, you call a member function in the object. It will read the data item and return the value to you. The data is hidden, so it is considered as safe and far away from accidental alternation. Data and its functions are said to be encapsulated into a single entity.
Encapsulation
EncapsulationPrivate data
Public data
Calling object
Polymorphism is a key to the power of OOP. It is the concept that supports the capability of data to be processed in more than one form.
Polymorphism
pollymurphism
What is your
name???
amit
sanjay
prakash
Pre processing directive.
Header files Iostream.h Input output stream header file.
Containing Cin and cout menthod
#include
C++ is totally case sensitive language.
Important note
cout<<“ welcome ”;
◦ cout = method◦ << = operator◦ “welcome “ = content to write◦ ; = statement termination
Writing on screen
Int k; cin>>k;
◦ cin = method◦ >> = operator◦ k = variable name to store data◦ ; = statement termination
Reading the data from keyboard
int I,j,k,l,m;
cin>>I>>j>>k>>l>>m;
◦ On Screen : 10 20 30 40 50◦ On memory
i = 10 j = 20 k = 30 l = 40 m = 50
Reading multiple values
#include<iostream.h> #include<conio.h> #include<stdio.h>
Void main() {
◦ Clrscr();◦ Cout<<“my first program in c++”;◦ Getch();
}
My first program
Registered and reserved words of c++ are known as a key word.
Not use to create variables.
Key word
List of Keywords asm double new switch auto else operator template break enum private this case extern protected try catch float public typedef char for register union class friend return unsigned const goto short virtual continue if signed void default inline sizeof volatile delete int static while do long struct
List of registered keywords of c++
Brackets [ ] opening and closing brackets indicatesingle and multidimensional array subscript.
Parentheses ( ) opening and closing brackets indicate functions calls, function parameters for grouping expressions etc.
Braces { } opening and closing braces indicate the start and end of a compound statement.
Comma , it is used as a separator in a function argument list.
Semicolon ; it is used as a statement terminator. Colon : it indicates a labelled statement or conditional
operator symbol. Asterisk * it is used in pointer declaration or as
multiplication operator. Equal sign = it is used as an assignment operator. Pound sign # it is used as pre-processor directive.
Punctuators
Char Integer Float Double Boolean
Data types
If condition If else condition If else if condition Switch case
Break statement Continue statement
Control statement
If(condition) {
◦ Executable part }
If condition
If(condition){
execute when condition ins true}else{
execute when condition is false}
If else
If(condition 1){
execute if condition is true}else if( condition 2){
execute when condition 1 is false and condition 2 is true
}
If else if
Switch(parameter) {
◦ Case (condition):◦ {◦ executable part;◦ Break;
}◦ Case (condition):◦ {◦ executable part;◦ Break;
} }
Switch case
Looping structure
Entry control loop
• For loop• While loop
Exit control loop
• Do while loop
While(condition) {
◦ Executable part◦ Increment / decrement;
}
While loop
Do {
◦ Executable part;◦ Increment / decrement
}while(condition);
Do while loop
Note : do while loop compulsory execute once
For(initialization;condition;increment/decrement){◦ Executable part
}
For loop
Arithmetic Logical Conditional Relational Increment / decrement Special Assignment Urinary / short hand
Operator
+ ( summation ) - ( subtraction ) / ( division ) * ( multiplication ) % ( modulation )
Arithmetic
|| ( or sign ) && ( and sign ) ! ( not sign )
Logical
Condition 1 Condition 2 ResultTrue False FalseFalse True FalseFalse False FalseTrue True True
And (&&) operator( flow chart)
Condition 1 Condition 2 ResultTrue False TrueFalse True trueFalse False FalseTrue True True
Or (||) operator ( flow chart)
Condition 1 condition 2 ResultTrue False FalseFalse True FalseFalse False TrueTrue True False
Not ( ! ) operator flow chart
> ( greater than) < ( less than) >= ( greater than equal) <= ( less than equal ) == ( equals to ) != ( not equals )
Relational
(condition? true: false)
conditional
Special operator , ( comma operator )
Ex. int a, b, c;
++ --
Pre increment / decrement◦ ++ Variable name◦ -- variable name
Post increment / decrement◦ variable name ++◦ variable name --
Increment / decrement
Variable name += Variable name +- Variable name +/ Variable name +* Variable name +%
Compound assignment
Ex cout<<“string 1” << “string 2” ;
Concatination
All the statement of c ++ are terminated by ◦ ;◦ (semi colon )
Must remember
String functions Math functions Character functions
Inbuilt functions
Header file◦ String.h
Functionsstrlenstrrevstrcpystrcmpstruprstrlwr
String functions
Header file◦ math.h
MinMaxRoundSqrtAbsFloorCeil
Math functions
Header file◦ Ctype.h
◦ Getch◦ Getche◦ Isdigit◦ Isalpha◦ Isalnum◦ Isspace
Character functions
Define in main four type.
No parameter no return value No parameter with return value With parameter no return With parameter with return
User define functions
Abc()
Void Abc() {
◦ Executable part }
No parameter no return value
Int I = abc();
Int abc(){
return 5;}
note : value of I = 5
No parameter with return
Abc(5,10);
Void Abc(a,b) {
◦ Cout<<5+10; }
With parameter no return
Int I = abc(5,10);
Int abc(a,b); {
◦ Return a + b; }
Value of I = 15.
With parameter with return value
Single dimention Multi dimention
◦ Collection of same data type.
◦ Int a[0];
Array
Index of array start with 0 (zero)
Array cont…..
Index
10A[0]
A[1]
A[2]
A[3]
20
30
40
Int A[4]
value
Ex. Int a[4][3]◦ 4 rows◦ 3 columns◦
Multi dimension array
a[1] 40 50 60
a[2] 70 80 90
a[3] 100 110 120
a[0] 10 20 30
index a[0] a[1] a[2]
a[1][1] = 50
User define data type
Key word Enum use to store only user define data
enum day = {“Sunday” , ”Monday” , ”Tuesday”}
Index start from 0
Ex index of Sunday is 0.
Enumerated data type
Collection of different data type
User define data type
Access by . (Dot)
Define with struct keyword
structure
struct structure name {
Variable data type variable name Variable data type variable name Variable data type variable name
Up to n variables. . .
};
syntax
struct std {
◦ int rn;◦ float per;
}; Void main() {
◦ std s;◦ S.rn = 915;
}
example
Use to define method and scope of method
Use :: to define scope
Define methods in class and out side of class also.
Scope resolution operator
Return type class name :: method name( list of parameters)
Syntax
class abc {
◦ Public:◦ Void msg();
};◦ void abc :: msg()◦ {
Executable part◦ }
example
Class : Collection of methods and variables. Collection of private and public data.
Object : Instants that Use to access functionality of class.
Class and object
class class_name {
Public : Methods Variables
};
Class
Return type method name ( list of parameters)
{◦ Executable part◦ [ return data ]
};
Method
Class name object name;
Ex.abc a;
Class name abcObject name a
Creating object
Create memory space on RAM.
Calling when creating object of any class
All class contains 1 default constructor.
Constructor name and class name both are same.
Default constructor not take any parameters.
Constructor
About constructor
A constructor is a special member function that initializes the objects of its class.It is special because its name is the same as the class name. It is invoked automatically whenever an object is created. It is called constructor because it constructs the values of data members of the class. It does not have any return type, not even void.
class abc {
◦ public:◦ abc()◦ {
Executable part◦ }
};
Constructor example
Use to delete object of any class
Call by ~ sign.
Destructor never return any kind of values.
Destructor
class abc {
public :◦ ~ abc()◦ {
◦ } }
Destructor example
class abc {
public : void msg() {
cout<<“welcome ”; };
}; void main {
◦ abc a;◦ a.msg();
} o/p = welcome
Accessing method through object
Re usability of any class Extends on class in another class Code re usability Access methods and variables of super
class Inherit functionality of super class. Use of pre define class
inheritance
Mainly 5 type of inheritance available in c++
Single level inheritance Multi level inheritance Multiple inheritance Hierarchical inheritance Hybrid inheritance
Type of Inheritance in c++
Base class Derived classAccess public private
protectedspecifierpublic public private
protectedprivate Not Not Not
inherited inheritedinherited
protected protected protected protected
Mode of inheritance
Ex. Functionality of class A use in class B
Single level inheritance
A
B
Multi level inheritance
a
b
c
d
Multiple inheritance
c
a b
Hierarchical inheritance
a
b c d
Combination of hierarchical and multiple
Hybrid inheritance
a
d
b b
Remember Available types of inheritance is
◦ Single level inheritance◦ Multi level inheritance◦ Multiple inheritance◦ Hierarchical inheritance◦ Hybrid inheritance
Example and syntaxes of inheritance
Ex. Functionality of class A use in class B
Single level inheritance
A
B
Base Class name : mode of inheritance super class name
Different Modes◦ Public◦ Private◦ Protected
Syntax of single level inheritance
class abc {
◦ Methods and variable };
class xyz : public abc {
◦ Methods and variable };
Single level inheritance example
Multi level inheritance
a
b
c
d
Class name (parent) { } Class name(child):access specification class
name( parent class ) { } Class name (sub child) : access specification
class name (parent class)
Syntax of multilevel inheritance
Class demo{}
Class demo1: public demo{}
Class demo2 : public demo1{}
example
Multiple inheritance
c
a b
Class class name{}class class name{}class class name : access specification class name ( parent 1 ), (parent 2 )
Syntax of multiple inheritance
Class demo{}
Class demo1{}
Class final : public demo, public demo1{}
Example
Hierarchical inheritance
a
b c d
Class class name{}
Class calss name : access specification class name{}
Class class name : access specification class name{}
Hierarchical inheritance syntax
Class demo{}
Class demo1 : public demo{}
Class demo2 : public demo{}
Example
Combination of hierarchical
Hybrid inheritance
a
d
b b
Class class name{}
Class class name : access specification class name{}
Class class name : access specification class name{}
Class class name : access specification class name, access specification class name
{}
Hybrid inheritance syntax
Class demo {} Class demo1 : public demo {} Class demo2 : public demo {} Class final : public demo1, public demo2 {}
examle
A file is a collection of logically related records. A program usually requires twotypes of data communication.
File handling
File Handling in c ++Data Type Description
ofstream This data type represents the output file stream and is used to create
files and to write information to files.ifstream This data type represents the input file
stream and is used to read information from files.
fstream This data type represents the file stream generally, and has the capabilities of
both ofstream and ifstream which means it can create files, write information to files, and read information from files.
(i) Writing data on the datafile:◦ The data flows from keyboard to memory and from
memory to storage device.
◦ Keyboard —> memory —> hard disk/floppydisk
(ii) Reading data from datafile:◦ The data flows from storage device to memory and
from memory to output device, particularly monitor.
datafile —> memory — > output device (screen)
Flow of data
Open ModesMode Flag Description
ios::app Append mode. All output to that file to be appended to the end.
ios::ate Open a file for output and move the read/write control to the end of the file.
ios::in Open a file for reading. ios::out Open a file for writing. ios::trunc If the file already exists, its
contents will be truncated before opening the file.
Open filesfstream afile; afile.open("file.dat", ios::out | ios::in );
ofstream outfile; outfile.open("file.dat", ios::out | ios::trunc );
Closing file
FileName.Close();
Writing in a fileWhile doing C++ programming,
you write information to a file from your program using the stream insertion operator (<<) just as you use that operator to output information to the screen. The only difference is that you use an ofstream or fstream object instead of the cout object
Reading from a fileYou read information from a file into your
program using the stream extraction operator (<<) just as you use that operator to input information from the keyboard. The only difference is that you use an ifstream or fstream object instead of the cin object.
File has two associated pointers called input pointer (or get pointer) and output pointer (or put pointer). Each time an input or output operation takes place, the pointer moves automatically. There are two pointers.
seekg ( ) It moves get pointer to a specified location.
seekp ( ) It moves the put pointer to a specified location
File pointers
Ios:: beg ios:: curios::end
ios :: beg means start of the file ios :: cur means current position of the
pointer ios :: end means end of the file
File pointers
file
A pointer is a variable that represents the location (rather than the value ) of a dataitem such as a variable or an array element
Pointer
Pointer variables declare with * sign.
And pointer variables access with & sign.
How to declare pointer variables?
Int a = 10; Int b = &a;
◦ In above example variable “a” is integer type variable and variable “b” is also integer variable.
◦ Variable b store the reference of variable “a”and when we use the variable “b” it return the value of variable “a”.
Pointer example
Operator overloading is use to overload any predefined operators.
Create class and with operator method and write new code for any operator.
Operator overloading
class class_name{public :void operator sign of operator () {new logic for operator };};
Main method {
object and apply operator}
Syntax of operator overloading
Class demo{
◦ Public:◦ Void operator ++ ()◦ {
Cout<<“ ++ operator overloaded”;◦ }
};Void main(){
demo d;d++
}
Example
Class name is demo.Publicly overload ++ operator with simple message.d is object of demo class.whenever you apply ++ operator then compiler not increment any value in object,But print simple message on screen.
Explanation of previous program
Prepared by
Kalpesh chauhan&
Kaushik bhalodiya
Thank you