Introduction:

C++ was developed by Bjarne Stroustrup at Bell Labs during the early 1980s. It was designed to support the features of C such as efficiency & low-level support for system coding. New features added were classes with inheritance & virtual functions, were inspired from Simula67 language, & Operator overloading was inspired from Algol68. Described as superset of C, C++ has full support for object-oriented programming (OOPs).

Getting Started:

To write any C++ Program, you need a text editor. Text editor allows you to create & modify text files (Notepad++, Sublime, etc). After writing the code we must make sure that it is error-free, this process is known as Compilation & Compiler is used to make sure that our code is error-free. It converts the code into machine understandable code (object code) & also displays syntax errors (if present) in the program.

C++ programs can be created using any text editor. Some systems like Visual Studio & Code::Blocks provide an integrated program development environment under different operating systems (like Windows, Linux). IDE Provides a built-in text editor & a compiler. C++ programs can be also compiled using command-line tools (like g++ & clang++).

Writing a Simple C++ Program:

#include <iostream>
using namespace std;
            
int main() {
    cout << "Hello, World.";
    return 0;
 }

Program Explanation:

Here the #include <iostream> in the program deals with including of header file (iostream is Input-Output Stream, also known as Preprocessor Directive) it is needed to support all built-in functions like cout (in this example), using namespace std; allows us to access elements from Standard C++ Library.

The the fourth line is the Main Function within the body of which you start writing the code for your program. Every C++ Program must include one & only one main function.

The code written between the curly braces { } is the program body, the 5th line will output the text enclosed in quotation marks ("") on the console. The sixth line return 0; is used to indicate that the program is executed successfully.

Program Output:

Hello, World.

Data Types:

The chart below shows various data types in C++,

Basic Datatypes:

  1. int: It stands for 'integer' and is used to represent whole numbers.
  2. char: It stands for 'character' and is used to represent characters such as letters.
  3. float: It is used to represent decimal numbers with upto 6-7 digits.
  4. double: It is similar to float but can hold more decimal places with upto 15-16 digits.
  5. void: It is used as the return type for functions that do not return a value.

Variables:

Variables are used to store information/data. The data stored in a variable can be changed during program execution. In C++ all variables must be declared before use.

Rules for Declaring Variables in C++:

  1. Variable names must start with a letter (A to Z) & (a to z).
  2. Data type must be specified before declaring the variable name.
  3. Keywords (like int, float, return, char) cannot be used as variables name.
  4. Variables with two same names can't be declared.
  5. Variables cannot contain whitespaces.
  6. Variables cannot contain special characters except underscores.

Syntax for Declaration of a Variable:

datatype variable_name;

Example:

#include <iostream>
using namespace std;

int main() {
    int myVar = 58;  
    /*Declares a variable named myVar 
    and assigns integer value of 58 to it*/
    return 0;
}

Constants:

Constants are declared with the "const" keyword, a type, their name, and an assignment of their constant value. This value must match the declared type, & its fixed (constant) for the duration of the programs.

Example:

#include <iostream>
using namespace std;
        
int main() {
    const int pie = 3.14;  
    /*Declares a constant named pie
    and assigns integer value of 3.14 to it*/
    return 0;
}

Congratulations!

Welcome to the programming club! You finished learning the basics of C++!