C++ theory

Detail description about C++

1. C++ Theory

2. Object Oriented Programming language

3. C++ is an extension to C Programming language. It was developed at AT&T Bell Laboratories in the early 1980s by Bjarne Stroustrup . It is a deviation from traditional procedural 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++

4. Inheritance Polymorphism Encapsulation Oop Concepts. . .

5. 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

6. inheritance vehicle 2 wheeler 4 wheeler honda Yamaha tata mahindra

7. 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

8. Encapsulation Private data Public data Calling object

9. 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

10. pollymurphism What is your name??? amit sanjay prakash

11. Pre processing directive. Header files Iostream.h Input output stream header file. Containing Cin and cout menthod #include

12. C++ is totally case sensitive language. Important note

13. cout <<“ welcome ”; cout = method << = operator “welcome “ = content to write ; = statement termination Writing on screen

14. Int k; cin >>k; cin = method >> = operator k = variable name to store data ; = statement termination Reading the data from keyboard

15. 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

16. #include< iostream.h > #include< conio.h > #include< stdio.h > Void main() { Clrscr (); Cout <<“my first program in c++ ”; Getch (); } My first program

17. Registered and reserved words of c++ are known as a key word. Not use to create variables. Key word

18. 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++

19. Brackets [ ] opening and closing brackets indicate single 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

20. Char Integer Float Double Boolean Data types

21. If condition If else condition If else if condition Switch case Break statement Continue statement Control statement

22. If(condition) { Executable part } If condition

23. If(condition) { execute when condition ins true } else { execute when condition is false } If else

24. 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

25. Switch(parameter) { Case (condition): { executable part; Break; } Case (condition): { executable part; Break; } } Switch case

26. Looping structure

27. While(condition) { Executable part Increment / decrement; } While loop

28. Do { Executable part; Increment / decrement }while(condition); Do while loop Note : do while loop compulsory execute once

29. For( initialization;condition;increment /decrement) { Executable part } For loop

30. Arithmetic Logical Conditional Relational Increment / decrement Special Assignment Urinary / short hand Operator

31. + ( summation ) - ( subtraction ) / ( division ) * ( multiplication ) % ( modulation ) Arithmetic

32. || ( or sign ) && ( and sign ) ! ( not sign ) Logical

33. Condition 1 Condition 2 Result True False False False True False False False False True True True And (&&) operator ( flow chart)

34. Condition 1 Condition 2 Result True False True False True true False False False True True True Or (||) operator ( flow chart)

35. Condition 1 condition 2 Result True False False False True False False False True True True False Not ( ! ) operator flow chart

36. > ( greater than) < ( less than) >= ( greater than equal) <= ( less than equal ) == ( equals to ) != ( not equals ) Relational

37. (condition? true: false) conditional Special operator , ( comma operator ) Ex. int a, b, c;

38. ++ -- Pre increment / decrement ++ Variable name -- variable name Post increment / decrement variable name ++ variable name -- Increment / decrement

39. Variable name += Variable name +- Variable name +/ Variable name +* Variable name +% Compound assignment

40. Ex cout <<“string 1” << “string 2” ; Concatination

41. All the statement of c ++ are terminated by ; (semi colon ) Must remember

42. String functions Math functions Character functions Inbuilt functions

43. Header file String.h Functions strlen strrev strcpy strcmp strupr strlwr String functions

44. Header file math.h Min Max Round Sqrt Abs Floor Ceil Math functions

45. Header file Ctype.h Getch Getche Isdigit Isalpha Isalnum Isspace Character functions

46. 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

47. Abc () Void Abc () { Executable part } No parameter no return value

48. Int I = abc (); Int abc () { return 5; } note : value of I = 5 No parameter with return

49. Abc (5,10); Void Abc ( a,b ) { Cout <<5+10; } With parameter no return

50. Int I = abc (5,10); Int abc ( a,b ); { Return a + b; } Value of I = 15. With parameter with return value

51. Single dimention Multi dimention Collection of same data type. Int a[0]; Array

52. Index of array start with 0 (zero) Array cont….. Index 10 A[0] A[1] A[2] A[3] 20 30 40 Int A[4] value

53. 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

54. 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

55. Collection of different data type User define data type Access by . (Dot) Define with struct keyword structure

56. struct structure name { Variable data type variable name Variable data type variable name Variable data type variable name Up to n variables. . . }; syntax

57. struct std { int rn ; float per; }; Void main() { std s; S.rn = 915; } example

58. 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

59. Return type class name :: method name( list of parameters) Syntax

60. class abc { Public: Void msg (); }; void abc :: msg () { Executable part } example

61. Class : Collection of methods and variables. Collection of private and public data. Object : Instants that Use to access functionality of class. Class and object

62. class class_name { Public : Methods Variables }; Class

63. Return type method name ( list of parameters) { Executable part [ return data ] }; Method

64. Class name object name; Ex. abc a; Class name abc Object name a Creating object

65. 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

66. 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.

67. class abc { public: abc () { Executable part } }; Constructor example

68. Use to delete object of any class Call by ~ sign. Destructor never return any kind of values. Destructor

69. class abc { public : ~ abc () { } } Destructor example

70. class abc { public : void msg () { cout <<“welcome ”; }; }; void main { abc a; a.msg(); } o/p = welcome Accessing method through object

71. 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

72. 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++

73. Base class Derived class Access public private protected specifier public public private protected private Not Not Not inherited inherited inherited protected protected protected protected Mode of inheritance

74. Ex. Functionality of class A use in class B Single level inheritance A B

75. Multi level inheritance a b c d

76. Multiple inheritance c a b

77. Hierarchical inheritance a b c d

78. Combination of hierarchical and multiple Hybrid inheritance a d b b

79. Remember Available types of inheritance is Single level inheritance Multi level inheritance Multiple inheritance Hierarchical inheritance Hybrid inheritance Example and syntaxes of inheritance

80. Ex. Functionality of class A use in class B Single level inheritance A B

81. Base Class name : mode of inheritance super class name Different Modes Public Private Protected Syntax of single level inheritance

82. class abc { Methods and variable }; class xyz : public abc { Methods and variable }; Single level inheritance example

83. Multi level inheritance a b c d

84. 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

85. Class demo { } Class demo1: public demo { } Class demo2 : public demo1 { } example

86. Multiple inheritance c a b

87. Class class name { } class class name { } class class name : access specification class name ( parent 1 ), (parent 2 ) Syntax of multiple inheritance

88. Class demo { } Class demo1 { } Class final : public demo, public demo1 { } Example

89. Hierarchical inheritance a b c d

90. Class class name { } Class calss name : access specification class name { } Class class name : access specification class name { } Hierarchical inheritance syntax

91. Class demo { } Class demo1 : public demo { } Class demo2 : public demo { } Example

92. Combination of hierarchical Hybrid inheritance a d b b

93. 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

94. Class demo {} Class demo1 : public demo {} Class demo2 : public demo {} Class final : public demo1, public demo2 {} examle

95. A file is a collection of logically related records. A program usually requires two types of data communication. File handling

96. 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.

97. ( 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

98. Open Modes Mode 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.

99. Open files fstream afile ; afile.open ("file.dat", ios ::out | ios ::in ); ofstream outfile ; outfile.open ("file.dat", ios ::out | ios :: trunc );

100. Closing file FileName.Close ();

101. Writing in a file While 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

102. Reading from a file You 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.

103. 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

104. Ios :: beg ios :: cur ios ::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

105. A pointer is a variable that represents the location (rather than the value ) of a data item such as a variable or an array element Pointer

106. Pointer variables declare with * sign. And pointer variables access with & sign. How to declare pointer variables?

107. 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

108. Operator overloading is use to overload any predefined operators. Create class and with operator method and write new code for any operator. Operator overloading

109. class class_name { public : void operator sign of operator () { new logic for operator }; }; Main method { object and apply operator } Syntax of operator overloading

110. Class demo { Public: Void operator ++ () { Cout <<“ ++ operator overloaded”; } }; Void main() { demo d; d++ } Example

111. 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

112. Prepared by Kalpesh chauhan & Kaushik bhalodiya

113. T h a n k y o u