Introduction to C++

1. Introduction to C++ Sayed Ahmed Just E.T.C Technologies Inc. Just E.T.C. Education Inc.

2. C and C++ • C++ is based on and an extension to C • Knowing similarities and dissimilarities between C and C++ will help • to select the right language for your application development

3. C++ Program Elements • Comments: • Header File: #include <iostream> • Namespace: A defined collection of symbols and variable names within an application • The main () function: must have in a program • Parentheses: A function/code block name is followed by Parentheses () • Braces: Boundary of code blocks

4. C++ Program Elements • Variables: Used to contain values. Think about variables in Mathematics • Statements: An instruction to the computer hardware to perform specific action. • Statement Terminator: a semicolon • Function calls: • One function can call another function. • It's just a transfer of control from one code block to another code block. • However, the control comes back to the caller again.

5. How does a C++ program look like? • #include <iostream> • using namespace std; • int main() { • intstudentId; • count << "what is your student ID" << endl; • cin>> studentId; • count << "Student Id " << studentId << endl; • }

6. C++ Namespace • A C++ program must have a namespace; • C program ends with .c • where C++ program ends with .cpp • Information communication to and from c program is treated as stream. • cout and cin are used for the purpose • cout and cin are practically objects

7. C++ Variables • To store values • case sensitive • must start with letter • Supportteddatatypes: char, int, float, double, boolean, wchar_t • float: usually 32 bits - 6 digit after decimam, • double: 64 bits - 10 digit after decimal,

8. Variable Scope • Can be declared anywhere • Local: • inside functions • Static: • Inside functions but do not get destroyed after • Global: • Declared outside the functions • can be accessed from anywhere in the program • Formal/Parameter • Hidden variable: • if a local variable use the same name of a global variable the local variable = hidden variable • use scope operator :: to access the global variable inside that function

9. Array: • Group of variable • A group of variables of the same type • in c strings are null terminated arrays • C++ also supports a predefined string class/data type; • include <string>

10. Constant Value in C++ • in c, define XYZ 100 • in c++, const int val=1000

11. OOP Concepts • Enables Code Resuse • Enables Data Security from Unauthorized Access • Object: • Attribute + behaviors • Primary OOP Concepts • Encapsulation: • Inheritance: • - reduce development time • - reuse • -increase maintainability of the code • Polymorphism: • assign different uses to an entity based onthe context • Abstraction: • simple representation of an objet. • hide not essential attributes and behaviors

12. Object Oriented Paradigm: • Object Oriented Paradigm: • Define objects - toughest • define messages • define properties • --define attributes • --define behaviors • Object behavior analysis: • Understand the application • Derive Objects • Categorize Objects • Model process flow

13. Modetrn C++ Compliers • C++ Compliers Must Support: ANSI Standard • Internationalization • Template • Locales • Namespaces

14. Friend Class • Friend Class • Friend functions and inline functions provide faster, and efficient application • A function can be friend to any number of functions • Use function declaration to declare friend functions • Static Data Members and Static Members • Function - create the common members of classes (across objects)

15. Constructors and Destructors • Constructor • no return types • called at object creation • Destructor • no return type

16. Operator Overloading • Operator Overloading • Compile time polymorphism • runtime poly • - inheritance • virtual functions • Operator Overloading: • -unary • -binary • -arithmetic • -assignment • Note: C++ does not support overloading based on return type

17. Irrelevant • Early Binding/Late Binding • Access Modifiers absent = protected

18. Inheritance and Destructors • inheritance and destructors • Diamond Problem: Virtual Base Class • Overriding • Pure Virtual Function

19. I/O Stream and File Stream • manipulators • COUT, setw, right, setfill, flush, endl • fstreambase • fstream • ifstream • ofstream

20. C++ I/O and File Streams • Mode of file opening • ios::in • ios::out • Sscanf • Read formatted file data • ifstream • fin.getLine() • Random File Reading • seekg • seekp

21. I/O System • I/O System • Buffered file system • Stream classes • stream • istream--_IO_istream_withassign • ostream • Iostream • Cin is an instance of _IO_istream_withassign • Instance of _IO_ostream_withassign • cout • cerr

22. Stream formatting flags • Stream formatting flags • Can be used with setf(), unsetf() • ios::left • ios::dec • ios::fixed • ios::oct • ios::right • ios::scientific • ios::showbase • ios::showpoint • ios::showpos • ios::uppercase

23. Unformatted I/O Operations • Unformatted input/output • character • character array • strings • use text buffer • Can provide abstraction of the I/O device • functions for unformatted input and output • cin.read() • cin.gcount() • cout.write()

24. File Operations • Files • fstreambase • opening, manipulating, closing • fstream, ifstream, ofstream • mode ios::app, ios::ate, ios::binary, ios::in, ios::out, ios::trunc • fin.getline() • Get pointers • Random Operation Put pointers • pointers • Seekg() • Seekp() • Tellg() • Tellp()

25. Handling Exceptions • Handling Exceptions • runtime errors • Exceptions • try and catch block • throw statement • Uncaught Exceptions • Multiple Catch • ---------- • identified by operating systems • if not handled passed to op system exception as int, char ,class strings • how it passes through functions • Derived Class Exceptions • catch block hierarchy • place derived classes catch up

26. Virtual Functions and Run Time Poymorphism • runtime with virtual functions • shape • -draw • rect • tri • define overriding by placing function in each • Show why virtual function needed? • virtual base • pointer runtime polymorphism • pure virtual function • Late binding • base point to base - call derive function - runtime-dynamic

27. Standard Template Library • Templates create reusable code • STL provides some foundational items • --templatized functions and • --classes • These can be used to solve a variety of problems • Some STL Elements • Containers • Algorithms • Iterators • STLs are compatible across operating systems

28. Containers • Vectors • Lists • Maps • Containers • Sequence • Associative

29. Algorithms • function templates work with container templates of any type • algorithm header file • Iterators are objects to cycle through the containers • iterator header file needs to be included if iterators are used • Iterator type: • Random Access • Bidirectional • Forward • Input • Output

30. Vector and Array Comparison • Vector and Array Comparison • container - behave the same way - infinite

31. Lists • Lists: class • Bidirectional linear sequentially • Functions • begin() • end() • erase() • insert(); (template) • push_back(); • push_front(); • remove(); • splice();

32. Map • Associative Container • Map templates take two parameters • Functions: • begin(); • clear(); • count(); • empty(); • end(); • erase(); • insert(); • size()

33. Working with Templates • Working with Templates • Imagine a situation - complex + many data type • Overload may help but time consuming • template can help • object creation define data type • template overloading