C++ Object Oriented Programming: Core Concepts and Features
UNIT–I: Object Oriented Programming Concepts
1. Procedural Language and Object Oriented Approach
Procedural programming is a method in which a program is divided into small procedures or functions. It mainly focuses on the sequence of actions to be performed. Data and functions are treated separately, which may reduce security because global data can be accessed from different parts of the program. Languages like C follow the procedural approach. Object Oriented Programming (OOP), on the other hand, focuses on objects rather than functions. An object combines both data and the functions that operate on that data into a single unit. OOP is based on real-world concepts such as objects, classes, inheritance, and polymorphism. It improves program organization, security, code reuse, and maintainability. C++ is a language that supports object-oriented programming and is widely used for developing large and complex applications.
2. Characteristics of OOP
Object Oriented Programming has several important characteristics that make programming easier and more secure:
- Encapsulation: Binds data and functions together into a single unit called a class.
- Abstraction: Hides unnecessary implementation details and displays only essential information.
- Inheritance: Allows one class to acquire the properties and behaviors of another class.
- Polymorphism: Enables one function or operator to behave differently in different situations.
- Data Hiding: Restricts direct access to data members to protect against unauthorized access.
- Message Passing: Allows objects to communicate with each other through function calls.
3. User Defined Types
User-defined data types are created by programmers according to the requirements of a program. They help in organizing data more effectively and make programs easier to understand and maintain. In C++, user-defined types include classes, structures, unions, and enumerations. These types allow programmers to combine multiple data items into one logical unit. For example, a student record may contain a roll number, name, and marks together. User-defined types increase flexibility and improve code readability.
4. Polymorphism
Polymorphism means “many forms.” It allows the same function or operator to perform different tasks depending on the context. There are two main types:
- Compile-time polymorphism: Achieved through function overloading and operator overloading.
- Runtime polymorphism: Achieved through virtual functions and function overriding.
5. Encapsulation
Encapsulation is the process of combining data and the functions that operate on that data into a single unit called a class. It involves restricting direct access to some components of an object to protect the data from accidental modification. In C++, this is implemented using access specifiers: private, public, and protected.
Getting Started with C++
6. Syntax of C++
Syntax refers to the set of rules that define how programs are written in C++. A C++ program usually begins with header files, followed by the main function. Statements end with semicolons, and blocks of code are enclosed within curly braces. C++ is case-sensitive.
7. Data Types
Data types specify the kind of data a variable can store. C++ provides basic types (integer, float, char, double, boolean) and derived/user-defined types (arrays, pointers, structures, classes).
8. Variables
Variables are named memory locations used to store data values. Each variable has a specific data type. Variable names must follow specific rules, such as beginning with a letter or underscore and avoiding reserved keywords.
9. String
A string is a sequence of characters. C++ provides a string class that supports operations such as concatenation, comparison, and searching, automatically handling memory allocation.
10. Function
A function is a block of code designed to perform a specific task. Functions help divide large programs into smaller, manageable parts, improving code reuse and modularity.
11. Namespace
A namespace is a feature used to organize code and avoid naming conflicts. The standard C++ library uses the namespace std.
12. Exception
An exception is a runtime error. Exception handling allows programmers to detect and handle errors gracefully using try, throw, and catch blocks.
13. Operators
Operators are symbols used to perform operations on variables. Types include arithmetic, relational, logical, assignment, and bitwise operators.
14. Flow Control
Flow control statements determine the order of execution. This includes decision-making (if, switch) and looping (for, while, do-while).
15. Recursion
Recursion is a technique where a function calls itself repeatedly until a stopping condition is reached. It is useful for solving problems like factorial calculation or tree traversal.
16. Array
An array is a collection of elements of the same data type stored in contiguous memory locations, accessed via indexes.
17. Pointer
A pointer is a variable that stores the memory address of another variable, enabling dynamic memory allocation and efficient data handling.
18. Structure
A structure is a user-defined data type used to group related variables of different data types into a single unit.
UNIT–II: Abstracting Mechanism
19. Classes
A class is a blueprint for creating objects, combining data members and member functions into a single unit.
20. Private and Public
Access specifiers control the visibility of class members. Private members are restricted to the class, while public members are accessible from outside.
21. Constructor
A constructor is a special member function automatically called when an object is created to initialize it.
22. Destructor
A destructor is automatically called when an object is destroyed to release resources. It is identified by a tilde (~) symbol.
23. Member Function
Member functions are defined inside a class to operate on its data members, defining the behavior of objects.
24. Static Members
Static members are shared among all objects of a class. A static variable has only one copy in memory.
25. References
A reference is an alternative name for an existing variable. Unlike pointers, they cannot be null and must be initialized upon declaration.
Memory Management
26. new Operator
The new operator allocates memory from the heap during runtime.
27. delete Operator
The delete operator releases memory previously allocated by new to prevent memory leaks.
28. Object Copying
Object copying duplicates member values from one object to another. This can be shallow or deep depending on resource management.
29. Copy Constructor
A copy constructor creates a new object as a copy of an existing one, essential for deep copying in classes with dynamic memory.
30. Assignment Operator
The assignment operator (=) copies contents from one existing object to another. It can be overloaded for custom behavior.
31. this Pointer
The this pointer refers to the current object instance within a member function.
32. Input/Output
C++ uses streams (iostream) for input and output operations, providing a flexible way to handle data.
UNIT–III: Inheritance and Polymorphism
33. Derived Class and Base Class
Inheritance allows a derived class to acquire properties from a base class, promoting code reuse.
34. Different Types of Inheritance
- Single, Multiple, Multilevel, Hierarchical, and Hybrid inheritance.
35. Overriding Member Function
Function overriding occurs when a derived class provides a specific implementation for a function already defined in the base class.
36. Abstract Class
An abstract class contains at least one pure virtual function and cannot be instantiated; it serves as a template for derived classes.
37. Public and Private Inheritance
Defines the accessibility of base class members within the derived class.
38. Ambiguity in Multiple Inheritance
Occurs when a derived class inherits from multiple base classes that share member names. Resolved using the scope resolution operator (::).
39. Virtual Function
Enables runtime polymorphism by allowing the program to call the correct function based on the object type.
40. Friend Function
A non-member function granted access to the private and protected members of a class.
41. Static Function
A member function that belongs to the class rather than an object, accessible without an instance.
UNIT–IV: Exception Handling
42. Exception and Derived Class
Exceptions can be organized in a hierarchy, allowing for general or specific error handling.
43. Function Exception Declaration
Specifies which exceptions a function may throw, improving code reliability.
44. Unexpected Exception
Occurs when a function throws an exception not listed in its declaration.
45. Exception when Handling Exception
Requires careful management (nested try-catch) to prevent program termination during error recovery.
46. Resource Capture and Release
Known as RAII (Resource Acquisition Is Initialization), ensuring resources are cleaned up via destructors.
Template and Standard Template Library (STL)
47. Template Classes
Generic classes that work with any data type, reducing code duplication.
48. Template Declaration
Defining templates using parameters to create generic components.
49. Template Functions
Generic functions that handle multiple data types with a single definition.
50. Namespace
A region that provides scope to identifiers to prevent naming conflicts.
51. String
The STL string class provides dynamic, efficient text manipulation.
52. Iterators
Objects used to traverse elements in STL containers, acting like pointers.
53. Hashes
A technique for fast data retrieval using key-value mappings.
54. iostreams
Standard library components for input and output communication.
55. Other STL Types
Includes containers like vector, list, queue, stack, map, and set for efficient data management.