DEV Community: flaneuroffc

Variables, Data types, Operators.

flaneuroffc — Tue, 03 May 2022 13:20:45 +0000

The general rules for naming variables are:

Names can contain letters, digits and underscores
Names must begin with a letter or an underscore (_)
Names are case sensitive (myVar and myvar are different variables)
Names cannot contain whitespaces or special characters like !, #, %, etc.
Reserved words (like C++ keywords, such as int) cannot be used as names

Basic Data Types

The data type specifies the size and type of information the variable will store:

Data Type Size Description

*boolean 1 byte Stores true or false values
*char 1 byte Stores a single character/letter/number, or ASCII values
*int 2 or 4 bytes Stores whole numbers, without decimals
*float 4 bytes Stores fractional numbers, containing one or more decimals. Sufficient for storing 7 decimal digits
*double 8 bytes Stores fractional numbers, containing one or more decimals. Sufficient for storing 15 decimal digits

Operators are used to perform operations on variables and values.
C++ divides the operators into the following groups:

Arithmetic operators
Assignment operators
Comparison operators
Logical operators
Bitwise operators

C++ Variables

flaneuroffc — Wed, 27 Apr 2022 10:35:49 +0000

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

The setfill() method of Iomanip library in C++ is used to set the ios library fill character based on the character specified as the parameter to this method.

Setw function is a C++ manipulator which stands for set width. The manipulator sets the ios library field width or specifies the minimum number of character positions a variable will consume.

terminal commands

flaneuroffc — Tue, 19 Apr 2022 12:48:00 +0000

Change Directory

Command: cd (..)

What it does: This command will change the directory that you’re currently working with in the Terminal in order to execute other commands on a different directory, view the contents of a different directory or open a file in a different directory.

Listing Directory

Command: ls (-a)

What it does: Use this command after navigating into a directory using the cd command to view the contents (files and directories) inside of the current directory. Use the argument -l (ls -l) to get even more information about each of the files, including the permissions, owner and date created.

Create a directory

Command: mkdir

What it does: This command will allow you to create a directory (folder) right from the CLI. When you need a place to store new files, just use this command to add a new directory in the current working directory, or specify a full path to the location where you want the new directory to be placed.

Clear the Terminal screen of all previous commands

Command: Clear

What it does: It removes all previously typed commands from the Terminal view and gives you back a clean slate to work from. Instead of typing clear, you can also alternatively press Command+K to perform the same action.