Object-Oriented Programming (OOP) Concepts

• Procedural programming concentrates on functions.
• Object-oriented programming focuses on objects, bundling data and behavior.
• The shift to object-oriented languages is needed to better handle complex applications and promote reusability, maintainability, and security.
• OOP languages include C++, Java, and Python.
• OOP applications include Simulations, Games, Real-Time Systems, and GUI apps.
• Top-down approach breaks down a system into subsystems.
• Bottom-up approach builds a system from small modules.
• OOPL concepts/features include encapsulation, inheritance, polymorphism, abstraction, dynamic binding, and message passing.
• Objects can be represented using classes and structures.
• Class is a blueprint for creating objects.
• Object is an instance of a class.
• A student class can define attributes like name and rollNo.
• Abstraction hides details.
• Encapsulation binds data and methods.
• Inheritance acquires properties.
• Polymorphism can take many forms.
• Dynamic binding involves runtime linking.
• Benefits of OOP include reusability, scalability, ease of maintenance, better modeling, and security.
• Bjarne Stroustrup developed C++.
• iostream.h provides cin and cout for input/output.
• Namespace groups identifiers to avoid name conflicts.
• << is the output operator.
• >> is the input operator.
• The default return type of main in C++ is int.
• Cascading of input operators achieves chaining multiple input/output in one statement.
• The structure of a C++ program includes headers, namespace, class/functions, and main().
• Tokens are keywords, identifiers, constants, operators, and separators.
• 15 new keywords were added in C++, totaling 63 keywords.
• Identifiers are names for variables, functions, and classes, such as rollNo and Student.
• Basic data types in C++: int, float.
• New data type in C++: bool.
• User-defined data types in C++: class, struct, enum, union.
• Structure members have separate memory.
• Union members share memory.
• Default access for Class members is private; for Structure, it is public.
• Enumerated data type is a user-defined type with named constants, e.g., enum Color {RED, GREEN}.
• C is procedural, while C++ is OOP.
• C has no classes, but C++ has classes and objects.
• Reference variables create aliases.

Syntax and Output

• int &ref = x; outputs values and same addresses.
• New operators in C++: new, delete, ::, ., ->, typeid, const_cast, static_cast, dynamic_cast, reinterpret_cast.
• :: symbol is the scope resolution operator.
• It accesses global variables and defines functions outside the class.
• • (asterisk) is the dereferencing operator.
• Objects are created dynamically using the new operator.
• The delete operator deallocates memory allocated using new.
• Manipulators format output.
• endl inserts a newline.
• setw(n) sets the width.
• (int)5.5 converts a float to an int as an example of type casting.
• Types of expressions: arithmetic, logical, relational, assignment, and bitwise.
• Varieties of assignment expressions: simple (=) and compound (+=, -=).

Models

• Waterfall model is a sequential model.
• Implicit conversion is automatic type conversion by the compiler.
• Operator overloading redefines operators for user-defined types.
• An addition program has one or two function calls, depending on implementation.
• Function parts include declaration, definition, and calling.
• Types of functions in C++: main, inline, constructors, destructors, friend, virtual, static member, recursion, pure virtual.
• Inline functions reduce overhead.
• Friend functions access private data.
• Virtual functions enable runtime polymorphism.
• Inline functions are type-safe.
• Macros perform simple text substitution without type checking.
• Default arguments use trailing parameters only and are needed for flexibility.
• Const arguments prevent modification inside a function.

Function Overloading

• Same name, different signatures.
• Memory allocation: heap/stack for objects, code segment for functions, and static segment for static data.
• Array of objects, object as a parameter, object as a return value examples: Student s[5]; void func(Student s); Student func();
• Friend functions are needed in function overloading to access private data across classes.
• Output explanations depend on operator+ overloading definitions for c1+c2, c1+5, 5+c2.
• Operator overloading redefines operator behavior, with at least one operand user-defined.
• Types of constructors: default, parameterized, copy, and dynamic for flexibility and initialization.
• Operators that cannot be overloaded: sizeof, ::, .*, .?, typeid.
• Friend functions cannot overload the assignment (=) operator.
• Type conversions of classes use conversion constructors or operator overloading for type casting.
• Inheritance types: single, multiple, multilevel, hierarchical, hybrid.
• The default access specifier in C++ is private in class.
• Protected access allows derived classes to access base class members but hides them from outside the world.
• The diamond problem in inheritance is ambiguity when two parents inherit the same base class.
• Visibility of inherited members: Public -> Public, Protected -> Protected, Private -> Not inherited.
• Types of classes: friend, virtual, abstract, nested.
• Dynamic overloading is compile-time, while overriding is run-time (using virtual).
• Polymorphism is compile-time and run-time polymorphism.
• This pointer points to the current object instance.
• Example of a pointer to member functions and variables: Class A { void func(); }; void (A::*ptr)() = &A::func; (obj.*ptr)();