Documenting My CPP Journey Part#2

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 . 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^st way is to use" //" before a single line of text to make it unparsable by the compiler.

2. Multi-Line Comments: 2^nd 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

2. geeksforgeeks

3. tutorialspoint