C++ Fundamentals: Pre-Defined Functions

Functions in C++

• A function is a block of organized, reusable code that performs a single, related action.
• Functions operate on inputs and produce results when called.

Pre-Defined Functions

• C++ comes with libraries of predefined functions that can be used in programs.
• Example: sqrt() function, found in the cmath library.
• Predefined functions can be used to perform specific tasks.

Defining and Invoking Functions

• Functions can take zero, one, or more arguments.
• Functions can return only one value.
• Function syntax: return-type function_name(type value1, type value2).
• To invoke a function, call its name and pass in parameters if it takes arguments.

Example Program

• To use predefined functions, include the necessary libraries (#include ).
• Use the using namespace std; directive to access standard library functions.
• In the main() function, declare variables and use functions to perform calculations.
• Example: calculate the square root of a number using sqrt().

Classes and Objects

• A class is a user-defined data type that holds its own data members and member functions.
• Classes are essential for Object-Oriented Programming (OOP) in C++.

Class Definition

• Class names should start with an uppercase letter, and multiple-word names should have the first letter of each word capitalized.
• Classes contain data members and member functions, with access controlled by access specifiers.

Access Specifiers

• Public: accessible from anywhere
• Private: accessible only within the class where it is defined
• Protected: accessible within the class and its subclasses

Inheritance

• Inheritance allows a derived class to inherit properties and behaviors from a base class.
• It promotes reusability and establishes a relationship between the base and derived classes.
• Parent class (base class or superclass) and child class (subclass or derived class)

Polymorphism

• Polymorphism means "many shapes" and allows objects of different classes to be treated as objects of a common superclass.
• Method Overloading: same method name, different parameters
• Method Overriding: same method name and parameters in the superclass and subclass

UML Class Diagram

• A visual representation of the structure and relationships among classes in an object-oriented system.
• Provides a high-level overview of classes, attributes, methods, and associations.
• Consists of three sections: public, private, and protected.

Constructors and Destructors

• Constructors are special class functions used to initialize objects.
• Destructors are special class member functions that release memory reserved by an object when it goes out of scope.

Objects of Classes

• Objects are instances of a class, holding data variables and member functions.
• Each object has separate copies of data members and is initialized using constructors.
• Destructor is called when an object goes out of scope, releasing memory.