Documenting My CPP Journey Part#2
Tags: cpp, beginners, learninpublic
Published: 2023-03-19 01:15:56

---
title: Documenting My CPP Journey Part#2
published: true
date: 2022-12-01 08:21:04 UTC
tags: #cpp #beginner #learninpublic
canonical_url: https://theamazingatharva.hashnode.dev/documenting-my-cpp-journey-part2
---

# Introduction :

Welcome to my first series on #Hashnode where I will be documenting my journey of learning C++ **from scratch to advance** to develop my programming skills and later make some **interesting projects**. In this blog, I will be sharing what I learnt in C++ since I wrote my [previous blog](https://dev.to/atharva_salitri/documenting-my-cpp-journey-part1-1jni-temp-slug-979174) . In this tutorial, we can study the **variables and comments** withinside the C++ language. In our last lesson, I mentioned the primary shape of a C++ program, in which we understood the operation of the C++ code line through the line. **Do check it out** to be up to date with what I will be sharing in this one.

# Variables in C++ :

Variables are **containers** for storing data values.

In C++, there are different types of variables (defined with different keywords), for example:

- `int` - stores integers (whole numbers), without decimals, such as 123 or -123

- `double` - stores floating point numbers, with decimals, such as 19.99 or -19.99

- `char` - stores single characters, such as 'a' or 'B'. Char values are surrounded by single quotes

- `string` - stores text, such as "Hello World". String values are surrounded by double quotes

- `bool` - stores values with two states: true or false

### **Syntax for Declaring Variables in C++**

1. Data\_type Variable\_name = Value;

2. Ex: int a=10; char ch = p;

3. Ex: float a= 1.1 , b=6.5;

### Rules For Declaring Variables in C++

- Variable names in C++ can range from 1 to 255 characters.

- All variable names must begin with a letter of the alphabet or an underscore(\_).

- After the first initial letter, variable names can also contain letters and numbers. 

- Variable names are case-sensitive i.e it is treated differently depending on whether it is in capital or lower-case text.

- No spaces or special characters are allowed.

- You cannot use a C++ keyword (a reserved word) as a variable name.

### Scope of Variables in C++

In general, the scope is defined as the extent to which something can be worked with. In programming also the scope of a variable is defined as the extent of the program code within which the variable can be accessed or declared or worked with. There are mainly two types of variable scopes:

1. Local Variables: Variables defined within a function or block are said to be local to those functions. 

2. Global Variables: As the name suggests, Global Variables can be accessed from any part of the program.

For example, consider this code snippet --- it shows an example of a variable " **sum"** taken as an integer variable, which will store a value 5, and writing sum after the " **cout"** statement will show us the value of "sum" on the output window i.e 5.

```
#include<iostream>
using namespace std;

int global_variable = 2; 

int main(){
    int local_variable = 3;
    int sum = 5;
    cout<< "The value of variable int sum is "<< sum;
    return 0;
}

```

# Comments in C++ :

A well-documented program is a good habit for a programmer. Programs are easier to read and easier to debug. Comments are an important part of good documentation.

- In computer programming, comments are programmer-readable explanations or annotations in the source code of a computer program.

- Comments are statements that are not executed by the compiler and interpreter.

There are two ways to write comments :

1. **Single-Line Comments:** 1<sup>st</sup> way is to use" //" before a single line of text to make it unparsable by the compiler.

1. **Multi-Line Comments:** 2<sup>nd</sup> way is to use "/\*" as the opening and "\*/" as the closing of the comment. We then write text in between them. It includes multiple statements in the form of non-executable texts for better readability.

For example :

This program consists of both single-line and multi-line comments that do not affect the outcome of the code. `Compiling` and `executing` this program will just print the statement - "Comments are easy".

```
#include<iostream>
using namespace std;
// This is a single line comment 
/* this
is 
a 
multi
line 
comment */
int main(){
   cout<< "Comments are easy"<< sum;
    return 0;
}

```

# **Congratulations!**

You just learnt about **variables** and **comments** in C++ !!!

Thank you for joining me in my quest to conquer C++. In the next blog, well be talking more about the different **Data Types** in a C++ program, see you there, till then keep coding and keep learning.

# Credit To The Following Resource I Referenced :

1. [w3schools](https://www.w3schools.com/cpp/cpp_comments.asp)

2. [geeksforgeeks](https://www.geeksforgeeks.org/scope-of-variables-in-c/)

3. [tutorialspoint](https://www.google.com/search?q=case+sensitive+meaning&oq=case+sensitive+meaning&aqs=chrome..69i57.4155j0j1&sourceid=chrome&ie=UTF-8)