DEV Community: Mahesh

AI won't replace software engineers

Mahesh — Sun, 13 Apr 2025 16:45:37 +0000

1. The Ambiguity Gap: Translating Human Intent into Precise Code

Natural languages (like English which non software-engineers use) are inherently less precise than formal logic languages (like Python or mathematics which software-engineers use).
AI's Challenge: A single sentence in English can be interpreted in multiple ways, leading to different functional outcomes if directly translated into code. While AI can generate code from natural language prompts, it often struggles with nuance, implicit assumptions, and resolving ambiguities without clarification. It might generate syntactically correct code that doesn't match the user's actual intent or misses crucial edge cases hidden within the ambiguity.
The Human Edge: Experienced software engineers excel at bridging this gap. They ask clarifying questions, understand context, read between the lines of requirements, anticipate potential misunderstandings, and engage in dialogue to ensure the final code precisely matches the intended functionality and business logic. This interpretive and communicative skill is hard for AI to replicate.

2. Trust, Accountability, and High-Stakes Systems

Building and deploying software, especially in critical domains (finance, healthcare, infrastructure, security), involves significant risk. When errors occur, they can lead to catastrophic failures, data loss, financial damage, or even harm to individuals. Businesses won't trust AI with critical code like this because AI faces no consequences for errors, unlike humans who risk their reputation and job.
The Accountability Void: Currently, AI systems lack legal personhood and genuine accountability. If AI generates faulty code causing massive losses, who is responsible? The AI vendor? The company using the AI? The engineer who reviewed (or didn't review) the code? This lack of clear liability makes businesses hesitant to fully entrust mission-critical development solely to AI.
The Human Element of Trust: Trust in software development isn't just about code correctness; it's about understanding the reasoning behind design decisions, having confidence in the development process, and knowing there's a responsible human or team to fix issues and take ownership. Humans build this trust through demonstrated competence, communication, and accepting responsibility for their work.

developer tools list

Mahesh — Fri, 22 Sep 2023 05:08:05 +0000

termdown
- do not leave work in hand until countdown is running
taskwarrior
- note down all distractive thoughts in tasks-list during work, review them all after predefined time for work is over
google chrome with web site blocker
- website blocker will help in focusing on work by blocking social media
vscode with neovim
- neovim will increase code writing speed. To think clearly, a developer should be able to write code as fast as he can think
obsidian with excalidraw
- excalidraw diagrams are necessary to understand and create notes for complex concepts
google bard

Manage vps RAM usage by docker containers

Mahesh — Fri, 11 Aug 2023 03:44:53 +0000

I recently had an issue where I couldn't connect to my VPS server. I thought it was an internet connection issue, but it turned out to be high RAM usage on my server.

I tried to find a monitoring tool to help me figure out what was going on, but the information I found was too lengthy and didn't seem relevant to my specific issue.

In the end, I figured out a quick way to fix the problem myself. Here's what I did:

get list of docker containers according to their RAM/Memory-Usage using docker stats

docker stats --no-stream --format "table {{.Name}}\t{{.MemUsage}}" | sort -k 2 -hr
# --no-steam: by default docker stats is streams information, which sometimes hangs 
#    command line --no-stream ask stats one time instead of streaming
# sort -k 2: sort list considering 2nd column which is MemUsage here
# sort -hr: h represents human-redable number, r represents reverse (descending order)

shut down or delete unnecessory containers using docker stop

And that's it, you can check again the reduced RAM usage on vps server by running htop

Web Development Bookmarks

Mahesh — Sat, 29 Oct 2022 04:08:58 +0000

Hosting

Website Hosting
- Vercel
- contabo (vps-provider) + docker + docker-compose + traefik hub
Database Hosting
- Docker Image of MySQL, PostgreSQL, MongoDB, etc on VPS server
- Razorhost-cpanel - MySQL
- Railway.app - Postgresql, Redis,
- MongoDB-Atlas - MongoDB
Email hosting
- Razorhost-cpanel
- MailDev - for testing
Code Hosting
- Github
File Hosting
- minio on vps, rclone to backup or transfer minio-server
- Storj - 150 GB Free, $4/month/TB storage
- pCloud
- Contabo - $3/month/250GB
- Arweave - Permanent Hosting
Domains
- Hostinger (cheapest for 1st year)
- Google Domains (buy for upto 9 years)
VS-Code Hosting
- Gitpod - $25 / month
- CodeSandBox - $12 / month (does not work properly for now)
VPS / Server Hosting
- Contabo - good for long-term hosting, due to affordable yearly plans
- Dropbox droplets - good for quick testing due hourly pricing
Cpanel Hosting
- razorhost
File Transfer
- pcloud - 5GB, password-protected
File Backup
- contabo_object-storage
- pCloud - affordable lifetime plans
- notion - unlimited storage at $8/month
- backblaze - unlimited storage at $7/month
File Encryption
- rclone
Logo Creator
- Logo.com
- Hatchful

Frontend Stack

Framework
- Next.js, ReactJS
Development enviroment
- docker-devcontainer: use only when needed
State Manangment
- Jotai
Beatification
- TailwindCSS
- Preline
- DaisyUI
- React-Toastify
- SweetAlert2
- Animate.css

Avoid

NextAuth - documentation is not user friendly, not sufficient options for modification
Pocketbase - cannot delete columns in database once created
Appwrite - self-hosting is difficult
Hetzner - asks for identity verification

Git Repository Essentials

Mahesh — Sun, 16 Oct 2022 19:44:58 +0000

Theory

Git-repository is a collection git-branches

Sections / Areas in git-branch

There are primarily 5 sections / drives / spaces in every git-branch

Working Area: Any file you create or modify included automatically in working area
Staging / Index Area: Area where you temporarity save your current changes.
Stash Area: stack of temporary-changes. Storeas changes you want to remove now from file but want to include it later on. You need to use it mostly when two or more developers working on a same branch and you want to include changes from all of them one after another
Commit Area: contains stack of commits. Each commit is snapshot of code at the time commit is created. Save your changes permanently in git.
Remote Area: Backup / Sync your Commit Area on a remote server like Github or Bitbucket

Working Area <-> Staging Area
Working Area Staging Area -> Stash Area -> Working Area
Staging Area <-> Commit Area
Commit Area <-> Remote Area

Practical

Notes:

Refere all git commands using git --help
You can replace <file_path> with . in the following code to apply command on all files

Create and Delete git-repository

git init # create first branch (master-branch) in current folder and move all your files in working area

rm -rf .git  # remove all git drive / sections

Git Configuration

There are two git configurations - Global (default for new repository) and Local (for current repository)

# use --global flag, to update gobal-configuation file
git config -l   # list global and local git config
git config -e  # update local git-config file which is present at ".git/config"
git config user.name "John Doe" # update User/Author name
git config user.email johndoe@example.com
git config core.editor "code --wait"    # set vs-code default editor for git
git config core.editor "nano -w"       # set nano as default editor for git

Working Area

git status # see which files / changes present in which area # file-names in red color are in working_area
# file-names in green color are in staging_area

git diff <file_path> # see changes present in working-area
git restore <file_path>   # delete file-changes made working area
git clean -f # delete all files in working area
git clean -fd  # delete all files and directories in working area

Staging / Index Area

git diff --staged # see changes in present in staging_area
git add <file_path>   # move changes (newly created files or modification in previous files) to staging area
git restore --staged <file-path>   # move changes from staging_area to working_area

Stash Area

git stash # move all changes from working and staging area to stash_area
git stash list # list all blocks of temporariy changes
git stash pop  # move most-recent block from stash_area to working_area ( position{0} )
git stash clear # delete all blocks in stash

Commit Area

git commit -m '<message>'     # move changes from staging_area to commit_area
# <message> is short text giving information about changes made in the commit
git commit --amend -m '<message>'  # move from staging_area to commit_area, but replace last-commit instead of creating new-commit
git log  # view all commits in current branch
git log --oneline # view all commits without description
git log --oneline --graph --all  # view graphical representation of all branches
git diff <commit_id> # view changes present in commit_id

git revert <commit_ID> # remove all changes in given 'commit_ID'
git reset HEAD~1  # delete last commit and move changes from last-commit to working-area
# HEAD~2 will delete latest 2 commits, HEAD~3 will delete latest 3-commits and so on..

Remote Area

git remote add <remote_area_name> <remote_area_url> # add connection to the remote_area
# you can give any name you want to remote_area_name, devlopers normally use "origin" for their first / default remote_area
git remote -v  # list currently set remote_area / servers names and their areas
git remote remove <remote_area_name>   # remove connection with remote repository
git push <remote_area_name> <branch-name> # copy changes in commit-area to remote_area
git fetch <remote_area_name> <branch_name> # copy branch remote_area to commit_area
git pull <remote_area_name> <branch_name> # merge remote branch to current branch
git clone <remote_area_url> # copy git repository from remote server/area to current folder

# for https-url
git config --global credential.helper cache   # save github password so you don't have to type it again
git config --global --unset credential.helper  # remove cached credentials

Branch Management

git branch <branch-name> # Create a new branch containing all git commits of current git-branch
git checkout --orphan <name>  # create a fresh branch without commits from current-branch
git branch -d <branch-name> # delete branch
git branch -m <current-name> <new-name>  # Change branch name
git checkout <branch-name> # move to another branch
git branch --all  # list all local and remote branches

git merge <branch-name> # merge branch with  <branch-name> to current branch
git merge <branch-name> --allow-unrelated-histories  # merge branch whose git-history does not match with current branch, normally used to merge changes from another repository
git merge --abort   # stop current merge process if there are conficts in merge, and you don't want to resolve them now

Git Tags

git fetch --all --tags  # fetch all tags from remote
git checkout tags/<version> -b <branch-name>  # switch to a tag and create bracnh for it

Backup Github

Mahesh — Fri, 09 Sep 2022 23:13:57 +0000

Install: https://github.com/josegonzalez/python-github-backup

Backup All Repositories in account

github-backup <username> -t <personal-access-token> -o <output-directory> --repositories --private

Backup All Repositories in organization

github-backup <organization-name> -t <personal-access-token> -o <output-directory> --repositories --private --organization
# <organization-name> is case-sensitive

Check README.md of repositories for more information about the commands

Script donwloads all the branches of each repositores, to check them run git branch -a inside repositories

Download/Upload files on remote server

Mahesh — Fri, 12 Aug 2022 16:11:46 +0000

Upload File On Server

scp -i <ssh-private-key-path> <file-local-path>  <file-remote-destination>
scp -i ~/.ssh/work            ./notes2.txt       mahesh@example.com:/home/team1

Download File From Server

scp -i <ssh-privae-key-path> <file-on-server-path>                      <file-local-destionation>
scp -i ~/.ssh/work           mahesh@example.com:/home/team1/notes2.txt  ./

Remote Download on Server

wget <file-url>
wget https://ipfs.io/ipfs/QmNf1UsmdGaMbpatQ6toXSkzDpizaGmC9zfunCyoz1enD5/penguin/17.png

Cloud development environment for Team

Mahesh — Thu, 11 Aug 2022 11:16:05 +0000

Target

Manage/Create dev-environment on cloud linux-server for a team to avoid local-computer errors and collaborate on code with other team-members

Requirements

VPS (used Ubuntu 20.04 VPS while writing this)
Root access

Overview

User Creation
Team-Group Creation
Team-Folder for team to collaborate

Steps

User Creation

# create user accounts for your team member
useradd --create-home <username>  # create user with directory for him in `/home` with name equal to <username>
passwd <username> # set user password
chmod o-rwx /home/<username> # make folder private, so only folder-owner and root-user can view/modify files
# "o" == others, 
# "-" == remove permissions 
# "r" == read, "w" == write", "x" == execute


# Additonal commands
id <username> # list user's userid(uid) and primary-group(gid) amd secondary-groups(groups)
cat /etc/passwd # list all users
deluser --remove-home <username> # delete user alongwith his directory
cat /etc/passwd # list all users

User can now connect with his folder with ssh and vs-code using command: ssh <username>@<ip-address/domain-name>

Team-Group creation

There are two types of groups primary-group and secondary group:

Primary group: created at the time of user creation, group-name is same as user-name, listed in - /etc/passwd
Secondary group: used to grant certain privileges to a set of users, listed in - /etc/group

We are going to create "Secondary group" here.

groupadd <group-name> # create group
usermod -a -G <group-name> <user-name> # add user to the group, -a == append, -G == group

# Additional commands
cat /etc/group  # list all groups
getent group <group-name> # list all users of a group
groupdel <groupname>

Team-Folder for team to collaborate

mkdir <folder-name> # create a new folder for team
chgrp -R <group-name> <folder-name>  # change group of folder to team-group we created above
chmod g+rwx <folder-name> # give access of folder to it's group

Now team-members can work privately in their individual folders and switch to team-folder to collaborate on code with other team-members

Reference

Learning Rust

Mahesh — Sat, 23 Apr 2022 16:29:43 +0000

Publishing the syntax I learn in rust, so I can keep my thinking as clear as possible.

I will update the article whenever I learn new syntax

Rust playground: https://play.rust-lang.org/

Strings

Rust has 2 types for strings, str and String. String is a growable, heap-allocated data structure. str is an immutable fixed-length string somewhere in memory.

let word1: &str = "vidya mandir";
let word2: String = "sahyadri parvat".to_string();
println!("{:?} {:?}", word1, word2);

print

println!("{:?}", variable_name) prints integers, strings, vectors

Array/Vector

let mut vector1 = vec![34,35,60,40,15];  // create vector, mut == vector1 is mutable/modifiable
vector1[3]; // get element at index 3
vector1.push(47);  // push element to vector
vector1.pop(); // remove last element of the vector
vector1.len(); // get length of vector
println!("{:?}", vector1);  // print vector

// array with length 50 and all elements equal to 0
let vector2: [u16; 50] = [0; 50];

Convert

Number to String

let num1: u128 = 34034;
let num1_str: String = num1.to_string();

String to Number

let num2_str: String = "40304".to_string();
let num2: u128 = num2_str.parse().unwrap();

Combine strings

let a = "a";
let line = format!("{} + {}", a, "b");
println!("{:?}", line); // a + b

String to number-array

// split string to form a array of vectors
let numsInStr = "3 4 25 90 233".to_string();
let numsInVec: Vec<u32> = numsInStr
      .trim().split(' ')
      .map(|s| s.parse().unwrap())
      .collect();
println!("{:?}", numsInVec);

Loops

for loop

let arr1 = vec![34, 50, 90, 110];
for i in 0..arr1.len() {
    println!("{:?}", i);
}

Deploy and Verify smart contracts using Hardhat

Mahesh — Mon, 13 Sep 2021 08:17:14 +0000

For this tutorial we are going to deploy 3 smart contracts:

basic contract
erc20 contract
erc721 contract

Setup project

Install hardhat

npm init -y     
npm install hardhat

start hardhat project

Start project with npx hardhat.
Choose 'Create a basic sample project' from options
Download dependencies asked for download, if you missed them, then download them by running npm install @nomiclabs/hardhat-waffle ethereum-waffle chai @nomiclabs/hardhat-ethers ethers

Add contracts to deploy

Inside contracts directory put the the contracts you want to deploy.
I am putting 3 contracts as:

1. Basic contract (contracts/Greeter.sol)

//SPDX-License-Identifier: MIT
pragma solidity ^0.8.0;

import "hardhat/console.sol";

contract Greeter {
    string private greeting;

    constructor(string memory _greeting) {
        console.log("Deploying a Greeter with greeting:", _greeting);
        greeting = _greeting;
    }

    function greet() public view returns (string memory) {
        return greeting;
    }

    function setGreeting(string memory _greeting) public {
        greeting = _greeting;
    }
}

2. erc20 contract (contracts/PopatToken.sol)

// SPDX-License-Identifier: MIT
pragma solidity ^0.8.2;

import "@openzeppelin/contracts/token/ERC20/ERC20.sol";
import "@openzeppelin/contracts/token/ERC20/extensions/ERC20Burnable.sol";
import "@openzeppelin/contracts/access/Ownable.sol";

contract Popat is ERC20, ERC20Burnable, Ownable {
    constructor() ERC20("Popat", "PT") {}

    function mint(address to, uint256 amount) public onlyOwner {
        _mint(to, amount);
    }
}

As we are importing openzepplin files in our contract, hence we are going to install the OpenZepplin npm package in our project as:

npm install @openzeppelin/contracts

3. erc721 contract (contract/PikachuNFT.sol)

// SPDX-License-Identifier: MIT
pragma solidity ^0.8.2;

import "@openzeppelin/contracts/token/ERC721/ERC721.sol";
import "@openzeppelin/contracts/token/ERC721/extensions/ERC721Burnable.sol";
import "@openzeppelin/contracts/access/Ownable.sol";
import "@openzeppelin/contracts/utils/Counters.sol";

contract Pikachu is ERC721, ERC721Burnable, Ownable {
    using Counters for Counters.Counter;

    Counters.Counter private _tokenIdCounter;

    constructor() ERC721("Pikachu", "PK") {}

    function safeMint(address to) public onlyOwner {
        _safeMint(to, _tokenIdCounter.current());
        _tokenIdCounter.increment();
    }
}

Modify hardhat configuration (`hardhat.confi.js`):

1. Configure solidity versions

Hardhat supports projects that use different, incompatible versions of solc. You can configure Hardhat to use compiler versions compatible with those files like this:

module.exports = {
  solidity: {
    compilers: [
      {
        version: "0.8.4",
      },
      {
        version: "0.6.7",
      }
    ]
  }
}

This setup means that a file with a pragma solidity ^0.8.0, ^0.8.1, ..., ^0.8.4 will be compiled with solc 0.8.4 and a file with a pragma solidity ^0.6.0, ..., ^0.6.7 will be compiled with solc 0.6.7

2. Define network configuration

module.exports = {
defaultNetwork: 'rinkeby',
  networks: {
    rinkeby: {
      url: // NETWORK_ENDPOINT_RINKEBY,
      accounts: // [ACCOUNT_0_PRIVATE_KEY, ACCOUNT_1_PRIVATE_KEY]
    }
    namedAccounts: {
      account0: 0,
      account1: 1
    }
  }

In each network you define, put node-endpoint-url through which you are going to connect with the network as the value of url field, the most popular endpoint provider is: https://infura.io/
Get the private keys of the accounts from which you want to deploy the contract and put them as array as value of accounts field
In namedAccounts field, you have to define name of account, which you will use while writing deploy code. Value of each account-name is the index-of-account's private-key inside <network-name>.accounts: [] array

3. Define ethereum-api key

module.exports = {
  solidity: {
  etherscan: {
    apiKey: // ETHERSCAN_API_KEY
  }
}

4. Import npm packages required in config file

require("@nomiclabs/hardhat-waffle");
require('hardhat-deploy');

The final configuration file on is look like this:

// hardhat.config.js
require("@nomiclabs/hardhat-waffle");
require('hardhat-deploy');
require('dotenv').config()

module.exports = {
  solidity: {
    compilers: [
      {
        version: "0.8.4"
      }
    ]
  },
  defaultNetwork: 'rinkeby',
  networks: {
    rinkeby: {
      url: process.env.NETWORK_ENDPOINT_RINKEBY,
      accounts: [process.env.ACCOUNT_0_PRIVATE_KEY, process.env.ACCOUNT_1_PRIVATE_KEY]
    }
  },
  namedAccounts: {
    account0: 0,
    account1: 1
  },
  etherscan: {
    apiKey: process.env.ETHERSCAN_API_KEY
  }
};

You have to install dotenv package to use environment variables as used in above file, else you can also put values directly if your repository is not public.

Deploy Contracts

Install hardhat-deploy plugin as npm install hardhat-deploy and import it inside 'hardhat.config.js' file as:

require('hardhat-deploy')

Put all deploy scripts under 'deploy' folder so deploy-plugin can detect and execute them

1. Deploy script for Basic contract

// deploy/0_greeter.js
module.exports = async ({getNamedAccounts, deployments}) => {
    const {deploy} = deployments;
    const {account0, account1} = await getNamedAccounts();

    await deploy('Greeter', {
      from: account0,
      args: ['Mahesh is Learning HardHat!'],
      log: true,
    });
  };

2. Deploy script for erc20 cotract

// deploy/1_popatToken.js
module.exports = async({getNamedAccounts, deployments}) => {
    const { deploy } = deployments
    const { account0 } = await getNamedAccounts()
    await deploy('Popat', {
        from: account0,
        args: [],
        log: true
    })
}

3. Deploy script for erc721 contract

// deploy/2_pikchuNFT.js
module.exports = async ({deployments, getNamedAccounts}) => {
    const {deploy} = deployments
    const {account0} = await getNamedAccounts()
    await deploy('Pikachu', {
        from: account0,
        args: [],
        log: true
    })
}

As you can see deploy scripts are same for all type of cotracts, the deploy scripts finds the contract by looking at the name of cotract defined inside .sol file.
E.g. In Greeter.sol file we defined contract name as contract Greeter {, hence we are using that same contract name inside deploy script as await deploy('Greeter', {

Now, we are ready for the deployment and verification 👍

Deploy contracts

npx hardhat deploy    # deploy contracts to defaulNetwork
# OR
npx hardhat --network rinkeby deploy   # deploy contrats to a specific network

Vefify Contracts

npx hardhat etherscan-verify

You can see the progress and contract-addresses in the console when you execute above deploy and vefication commands.

My simple tutorial ends here. Happy Coding ! 😊

Why IT Industry is fastest growing Industry in the World

Mahesh — Sat, 08 Aug 2020 07:19:54 +0000

1. Easy entry for newcomer

The entry barrier for newcomer in IT industry is lowest compare to any other field. As almost anyone can learn any IT technology just by a computer and internet connection.

2. Automation

Once code is written for some work the work could be done millions or billions of times without any human need. Hence, unlike other industries, IT professionals can work heavy tasks in a short period.

3. Money

Automation leads to increased margins of profit for established IT companies. Hence the IT industry has the highest amount of money-flow inside it which leads to evolution of old technologies and invention of new-ones.

4. Free services to developers

The amount of free services the IT industry provides to its developers is unparalleled to any other industry.

Hence, the learning curve of new developers increases rapidly in a short period as there are almost no restrictions due to money on learning new technology.

5. Learning curve

As it is just a few clicks away to get any new information or a new skill. The learning curve in programming is way higher than in other industries.

Hence, the number of experts in technology is larger than in any other industry.

6. Millions of programmers & still counting

As it very easy to get in and the rapid learning, the number of programmers around the world increased exponentially and still increasing.

7. IT Industry penetration

As the IT industry is mainly based on Automation, precision & inventions, it is penetrating and becoming part of almost every other industry.

Competitive Programming setup in VS-Code

Mahesh — Wed, 05 Aug 2020 15:16:30 +0000

Note

Programming Languages Covered - C++, Java, Python
Code Editor used - VSCode
Operating Systems covered - Windows, Linux, MacOS

Target

Create an environment such that -

We could write 'input' inside a text-file
Click on a icon
And 'output' of the code will be shown in Terminal or will be written in a text-file

1. Create Folder

Create a new folder on desktop and open this folder inside VSCode
Create app.cpp, app.java, app.py in the folder
Also create input.txt in the folder with following text:

   This is line 1
   This is line 2

Download code-runner extension for VSCode and restart VSCode
Go to settings of VSCode with Cntr + ,
Click on top-right 'file-icon' (to open settings in JSON)
Set "code-runner.saveFileBeforeRun" as true
Keep this sfile open for further modification

2. C++ Setup

Download and install MinGW-w64 for Windows - compiler for C++
Execute g++ --version inside PowerShell to check if compiler is correctly installed
Paste following code inside app.cpp

#include <bits/stdc++.h>
using namespace std;

int main() {

   string word1, word2;             // memory-space for words
   cin >> word1 >> word2;           // insert first-word => word1 && second-word => word2
   cout << word1 << " " << word2;   // output "<word1> <word2>"

   return 0;
}

If yo are using Windows, Open PowerShell using Cntr + ~ (Choose 'PowerShell' as Default shell if not already) and run the following command

g++ app.cpp -o app; Get-Content input.txt | .\app   # write output in the powershell-termainal
# g++ app.cpp  => compile 'app.cpp' with g++
# -o app       => defining output file-name as 'app.exe'
# ;            => end of command
# Get-Content input.txt | .\app  => Execute 'app.exe' with content from 'input.txt'

# OR

g++ app.cpp -o app; Get-Content input.txt | .\app > output.txt   # write output inside 'output.txt' file

If your are using Mac or Linux, Open Bash/Terminal using Ctrl + ~ and run the following command

g++ app.cpp -o app && cat input.txt | ./app > output.txt

3. Java Setup

Download and Install Java - for compilation of Java Code
Execute java --version inside PowerShell to check if compiler is installed correctly
Paste following code inside app.java file

import java.util.*;
import java.lang.*;
import java.io.*;

/* IMPORTANT: class-name must be equal to file-name, here file-name is 'app.java', hence class-name is 'class app' */

class app
{
    public static void main (String[] args) throws java.lang.Exception
    {
      File input = new File("./input.txt");  // declare input
        Scanner scanner1 = new Scanner(input);  // declare scanner

      String word1 = scanner1.next();         // scan first-word
      String word2 = scanner1.next();         // scan second-word

      String word3 = word1 + " " + word2;
      // String line1 = sc1.nextLine();      // in-case if you want to scan complete line

      System.out.print(word3);         // output "<word1> <word2>"
    }
}

For Windows, open PowerShell and run command as -

javac app.java; java app    # output in the powershell-terminal
# OR
javac app.java; java app > output.txt   # write output inside 'output.txt'

# javac app.java   =>  compile '.java' file using javac into bytecode as '.class'
# ;                =>  end of previous-command
# >                => transfer output genereated to the a file
# java app         =>  execute '.class' file

For Linux or MacOS, Open Bash and run command as -

javac app.java && java app        # write output in bash-terminal
#OR
javac app.java && java app > output.txt  # write output in output.txt file

# javac app.java    => compile app.java to app.class
# &&                => and, bridge between two-separate commands
# java app          => execute '.class' file

4. Python Setup

Download and Install - Python for compilation of python code
Execute python --version inside PowerShell to check if Python is correctly installed
Paste following code into app.py

line1 = input()         # get 'first-line' as value of variable 'line1'
line2 = input()         # get 'second-line' as value of variable 'line2'

arr1 = line1.split()    # get array of individual words from 'line1'

print(arr1[0] + ' ' + arr1[1])  # output => "<word1> <word2>"

For Windows, open PowerShell and run -

Get-Content .\input.txt | python .\app.py       # output will print inside 'powershell'
Get-Content .\input.txt | python .\app.py > output.txt  # ouput will be written inside 'output.txt'

For Linux or MacOS, open Bash and run -

cat input.txt | python app.py     # write output insided terminal
cat input.txt | python app.py > output.txt    # write output inside file named - output.txt in the same folder

5. Execute PowerShell/Bash Commands with One-Click

Open VSCode settings (inside JSON format) as described in the Step-1
Comment out code for cpp, java and python inside "code-runner.executorMap": {} and add the json-code given below:

For WIndows

"cpp": "g++ $fileName -o $fileNameWithoutExt; Get-Content input.txt | .\\$fileNameWithoutExt",
"java": "javac $fileName; java $fileNameWithoutExt",
"python": "Get-Content .\\input.txt | python .\\app.py",

For Linux or Bash

"cpp": "g++ $fileName -o $fileNameWithoutExt && cat input.txt | ./$fileNameWithoutExt",
"java": "javac $fileName && java $fileNameWithoutExt",
"python": "cat input.txt | python app.py",

Now come to the file app.cpp or app.java or app.py file
Click on the 'horizontal-rectangle' icon on 'top-left' => Now you can see the 'output' of your code inside PowerShell/Bash terminal

In this way you can test your code with just 'one-click' (with writing input inside 'input.txt' file) before submitting on 'Competitive Programming Platform'.

If you find any problems or want to suggest improvements, please let me know in comments and I will modify this article.

DEV Community: Mahesh

AI won't replace software engineers

1. The Ambiguity Gap: Translating Human Intent into Precise Code

2. Trust, Accountability, and High-Stakes Systems

developer tools list

Manage vps RAM usage by docker containers

Web Development Bookmarks

Hosting

Frontend Stack

Avoid

Git Repository Essentials

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Sections / Areas in git-branch

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Notes:

Create and Delete git-repository

Git Configuration

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Stash Area

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Learning Rust

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print

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Deploy and Verify smart contracts using Hardhat

Setup project

Install hardhat

start hardhat project

Add contracts to deploy

1. Basic contract (contracts/Greeter.sol)

2. erc20 contract (contracts/PopatToken.sol)

3. erc721 contract (contract/PikachuNFT.sol)

Modify hardhat configuration (hardhat.confi.js):

1. Configure solidity versions

2. Define network configuration

3. Define ethereum-api key

4. Import npm packages required in config file

Deploy Contracts

1. Deploy script for Basic contract

2. Deploy script for erc20 cotract

3. Deploy script for erc721 contract

Vefify Contracts

Why IT Industry is fastest growing Industry in the World

1. Easy entry for newcomer

2. Automation

3. Money

4. Free services to developers

5. Learning curve

6. Millions of programmers & still counting

7. IT Industry penetration

Competitive Programming setup in VS-Code

Note

Target

1. Create Folder

2. C++ Setup

3. Java Setup

4. Python Setup

5. Execute PowerShell/Bash Commands with One-Click

Modify hardhat configuration (`hardhat.confi.js`):