DEV Community: Pooja Sanap

WHY DO QR CODES HAVE 3 BIG SQUARES?

Pooja Sanap — Tue, 25 Jan 2022 13:33:26 +0000

Almost all of us have seen QR codes before, they are like everywhere now, from making payments, or packaging gadgets or on business cards. Companies and even people nowadays use QR code to give information that is quickly accessible and can be seen even with a smartphone. But have you ever wondered why there are 3 big squares in each and every QR code we have come across.

First, let's take a look at what are these QR's actually?

So, basically, the term QR stands for Quick Response Code. QR codes are square barcodes (two-dimensional barcodes) that were first developed and used in Japan. Like any other barcode, a QR code is nothing more than a way to store information in a machine-readable optical label. The data contained by a QR code can be anything from simple text to email addresses, phone numbers, and so on.

QR codes store data using patterns of black dots and white spaces arranged in a square grid. These patterns can be scanned and translated into human-readable information, with the help of an imaging device, like a camera or a scanner.

But why these 3 big squares?

We can do an experiment to understand this:

Attached below is a reference key. You don't have to remember it, you can always look at it any time you need.

Now, I want you to compare the below character to the key and identify it.

Well, that was pretty easy! Yes, you got it right !! It's number 5. (Even if you didn't find, there is nothing to be worried about, you can crosscheck now.)

Now, I want you to try this:

It's not that easy anymore, isn't it?
But now check the image below.

You can clearly see when the QR code has the squares, the smartphone or any scanning device and quickly figure out a way to rotate and resize the code, turning it to this(below image).

And now you can guess it, right?
Yes, absolutely, it's number 3.
This is why there are these 3 big squares.
They ensure the codes can be correctly read.

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10 Websites Every Programmer Should Know

Pooja Sanap — Wed, 08 Dec 2021 07:20:19 +0000

As a programmer, we come across a lot of websites for resources, documentation, how to-dos, answers and much more…
Here, in this article, we will be looking for top 10 websites which are important in our coding journey.

1. w3schools

w3schools is one of the most essential website for beginners as well as pros. It has tutorials, documentations, practice code spaces, paid courses, exercises and almost everything which a beginner needs.

2. GeeksForGeeks

GeeksforGeeks is another website providing all the references, blogs, practice problems, courses. They also have their student and campus ambassador programs.

3. HackerRank

HackerRank is a wonderful website to practice your coding skills and test your knowledge. You can also take certification test for free. You can also earn badges for solving problems on HackerRank.

4. HackerEarth

HackerEarth has little hard problems than on HackerRank. So if you have practiced well on HackerRank then HackerEarth is a good website to go ahead with along with Leetcode(next website)

5. Leetcode

Leetcode is good for interview preparations, they have a good range of questions. Also, you can participate in the coding contests organized by Leetcode.

6. CodeChef

CodeChef is the best website you can come across for Competitive Programming. CodeChef Competitions are held 3 times in every month. Also, there are many competitions which are organized on CodeChef by top institutes and universities.

7. Front End Mentor

If you have interest in front end development, then this is a good website to show off your skills. They also have challenges, which you have to complete and depend upon that you will earn credits.

8.CodePen

CodePen is also a useful website for your front end development skills. CodePen has challenges every week with a different theme. You can also check other people work, follow them and much more.
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9.Codeply

Codeply is a website where you can work with front end frameworks and libraries like Bootstrap, Angular, React, Vue and many more...

10.GitHub

No website is as important as GitHub is. GitHub is a project version control website. You can create unlimited private as well as public repositories. You can contribute to other people projects (Open Source). Also, it can work as a backup for your coding files and projects.

Hope you find it useful!
Thanks for reading!

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Git Cheat sheet

Pooja Sanap — Tue, 07 Dec 2021 09:52:12 +0000

Git is a version control (VCS) system for tracking changes to projects. These projects can be large-scale programs like the Linux kernel, but they can also be smaller scale projects like your own R development, homework assignments, papers, or thesis.

Using Git

to add name

git config --global user.name yourname

to add email

git config --global user.email youremail@yourdomain.com

to check name

git config --global user.name

to check email

git config --global user.email

to initialize empty git repository

git init

to show hidden files

ls - lart

to create blank files

touch file_name

to check status of file

git status

to commit file

git commit

to commit all files

git commit -a

to add file in current repository

git add file_name

to add all files

git add -A

-to add commit message

git commit -m "MESSAGE_HERE"

to match with last commit, i.e., to recover losses

git checkout file_name

to match all files with the last git commit

git checkout -f

to check all commits

git log

to check last 'n' commits (n should be a number)

git log -p -n

to get difference between working file and staged file

git diff

to get a list of the version history for the current branch.

ls

to directly commit files (skip staging area)

git commit -a -m "MESSAGE_HERE

to delete files

git rm file_name

to remove file from staging area

git rm --cached file_name

to get summarized status

git status -s

to create ignore files

touch .gitignore

to add new branches to git

git branch branch_name

to switch between branches

git checkout branch_name

to restore branch into master branch

git checkout master

to merge branches into master branch (user must be in master)

git merge branch_name

to create a branch and directly switch into it

git checkout -b branch_name

to add remote git repository

git remote add URL_HERE

to push branch into remote repository

git push repository_name branch_name

to clone the repository into local setup from a URL

git clone URL_HERE

to get remote URL from where the repository was cloned

git config --get remote.origin.url

to unstage the file, but preserve the file contents

git reset file_name

to undo all the commits after the specified commit and preserve the changes locally

git reset [commit]

to discard all history and goes back to the specified commit

git reset –hard [commit]

to show the metadata and content changes of the specified commit

git show [commit]

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