Introduction to C++

C++ is a general-purpose programming language developed as an extension of the C language. It provides features such as classes, objects, inheritance, polymorphism, and templates.

#include <iostream>

int main() {
    std::cout << "Hello World!";
    return 0;
}

The above program is a simple C++ program that displays a message.

C++ is useful for learning important programming concepts.

• It teaches programming fundamentals.
• It supports object-oriented programming.
• It provides high performance.
• It is used in many real-world applications.
• It helps build a strong programming foundation.

C++ is called a general-purpose language because it can be used to develop many different types of software.

• Desktop applications
• Games
• System software
• Embedded applications
• High-performance applications

C++ was developed from the C programming language. Many basic concepts of C are also found in C++, but C++ adds several additional programming features.

For example, C++ supports classes and objects, which are fundamental concepts of object-oriented programming.

C++ supports object-oriented programming, commonly called OOP. OOP organizes programs around objects and classes.

Important OOP concepts include:

• Class
• Object
• Encapsulation
• Inheritance
• Polymorphism
• Abstraction

C++ source code is normally compiled before it is executed. A compiler translates the source code into machine code that the computer can execute.

This compilation process helps C++ programs achieve high performance.

C++ source code is commonly saved using the .cpp file extension.

Example:

hello.cpp

The .cpp extension tells us that the file contains C++ source code.

Here is a simple C++ program:

#include <iostream>

int main() {
    std::cout << "Welcome to C++";
    return 0;
}

This program displays Welcome to C++ on the screen.

The #include directive is used to include a header file in a C++ program.

For example:

#include <iostream>

The iostream header provides functionality commonly used for input and output operations.

The iostream header is commonly used when a C++ program needs standard input and output functionality.

It provides objects such as std::cout and std::cin.

#include <iostream>

The main() function is the entry point of a normal C++ program. Program execution begins from the main function.

int main() {
    return 0;
}

In the following declaration, int specifies that the main function returns an integer value.

int main() {
    return 0;
}

The statement return 0; commonly indicates successful completion of the program.

The std::cout object is used to display output on the standard output stream.

#include <iostream>

int main() {
    std::cout << "Hello C++";
    return 0;
}

The insertion operator << is commonly used with std::cout to send data to the output stream.

std::cout << "Hello";

Here, the text Hello is sent to the standard output.

You can use multiple insertion operators in the same statement.

std::cout << "Name: " << "Rahul";

This prints both pieces of text in sequence.

The std::endl manipulator can be used to move the output to the next line.

std::cout << "Hello" << std::endl;
std::cout << "Welcome";

The escape sequence \n can also be used to create a new line.

std::cout << "Hello\n";
std::cout << "C++";

The second message will appear on the next line.

A statement is an instruction that tells the program to perform an operation.

std::cout << "Hello";

Most C++ statements end with a semicolon ;.

The semicolon is used to terminate many C++ statements.

int age = 20;
std::cout << age;

Forgetting a required semicolon can cause a compilation error.

C++ is case-sensitive. This means uppercase and lowercase letters are treated differently.

int age = 20;
int Age = 30;

Here, age and Age are different identifiers.

Comments are notes written inside source code. They are ignored by the compiler.

Single-line comment:

// This is a comment

Multi-line comment:

/*
   This is a
   multi-line comment
*/

A variable is a named memory location used to store a value.

int age = 20;

Here, age is an integer variable containing the value 20.

C++ provides several basic data types.

• int – integer values
• float – floating-point values
• double – double-precision floating-point values
• char – a character
• bool – true or false

int age = 20;
double price = 99.50;
char grade = 'A';
bool passed = true;

The std::cin object is commonly used to take input from the user.

#include <iostream>

int main() {
    int age;

    std::cin >> age;

    std::cout << "Age: " << age;

    return 0;
}

The extraction operator >> is commonly used with std::cin to read input.

int number;

std::cin >> number;

Many names from the C++ standard library are available inside the std namespace.

std::cout << "Hello";
std::cin >> age;

The std:: prefix specifies that cout and cin belong to the standard namespace.

#include <iostream>

int main() {

    int age;

    std::cout << "Enter your age: ";
    std::cin >> age;

    std::cout << "Your age is: " << age;

    return 0;
}

This program takes an age from the user and displays it.

C++ is used in many areas of software development.

• Game development
• Operating systems
• Desktop software
• Embedded systems
• Graphics applications
• High-performance software

• High performance
• Supports object-oriented programming
• Provides low-level programming capabilities
• Supports generic programming through templates
• Suitable for large and complex applications

In this C++ tutorial series, you will gradually learn C++ from basic concepts to advanced programming topics.

• C++ syntax and fundamentals
• Variables and data types
• Operators
• Conditional statements
• Loops
• Functions
• Arrays and strings
• Pointers and references
• Classes and objects
• Inheritance and polymorphism
• Templates
• Exception handling
• File handling
• STL
• Mini project