Daily Coding Challenges & Projects

Frontend Mini Project Challenge (Updated)

Focus : JavaScript Logical Puzzles & Debugging

Challenge :

Write a function flattenArray that flattens an arbitrarily nested array without using recursion.

// Input: [1, [2, [3, [4]], 5]]
// Output: [1, 2, 3, 4, 5]

Bonus Debug Task:

What's wrong with this code?

let nums = [1, 2, 3];
let squared = nums.forEach(num => num * num);
console.log(squared); // Fix the issue

Backend Challenge

Language Focus : C, C++, C#

C :

Task : Write a function to reverse a singly linked list using pointers.

C++ :

Task : Create a class BankAccount with deposit, withdraw, and balance check methods. Use proper encapsulation.

C# :

Task : Implement a simple console app that reads a CSV file of students and prints names of students with grades above 85.

Database Query Challenge

Problems on SQL - HR Database :

1. Write a SQL query to find employees who joined within the last 90 days.
2. Write a query to list employees who haven't received any salary increment in the past 2 years.

Data Structures & Algorithms Challenge

• Easy:
• Problem : Check if a string has balanced parentheses:
• Hint : Use Stack

			Example input: "{[()]}" → true, "{[(])}" → false
			

• Medium:
• Problem : Given a sorted array and a number target, find if two elements sum up to target.
• Hint : Two-pointer approach
• Hard:
• Problem : Given a list of words, implement an autocomplete system that returns words starting with a given prefix.
• Hint : Use Trie or Prefix Tree

Bug of the Day

Language Focus : C, C++, C#

C Bug:

Buggy Code:

int arr[3] = {1, 2, 3};
printf("%d", arr[3]); // What's wrong?

C++ Bug:

Buggy Code:

std::vector v = {1, 2, 3};
for (int i = 0; i <= v.size(); i++) {
    std::cout << v[i] << std::endl;
}

C# Bug:

Buggy Code:

int[] numbers = new int[5];
Console.WriteLine(numbers[5]); // Fix it

📋 Daily Micro-Project

Frontend Task : ( JS/CSS ):

Project :

Create a CSS-only animated loader that spins and pulsates using @keyframes.

Trivia: 5 Fun Facts

1. The first computer bug was an actual moth found in a computer in 1947.
2. Java was initially called “Oak”.
3. The first website is still online: info.cern.ch
4. Linux was created by Linus Torvalds in 1991.
5. Git was also created by Linus Torvalds for Linux kernel development.

Tool & Resource of the Day

Tool : Polypane

Description :A powerful browser for responsive web development and testing.

Features :Preview multiple screen sizes simultaneously, accessibility checks, and synchronized scrolling.

Link :https://polypane.app

Interview Question of the Day

Daily Interview Questions

Frontend :
1. What is the event loop in JavaScript?
2. How do arrow functions differ from regular functions in JS?
3. What are refs in React?
4. Explain Vue.js lifecycle hooks.

Backend :
1. Explain memory allocation in C.
2. What is the difference between stack and heap in C++?
3. What is garbage collection in C#?
4. How does multi-threading work in C#?

Database :
1. What is a foreign key in SQL?
2. Explain the purpose of the HAVING clause.
3. What are transactions in SQL?

Others :
1. What is a kernel in an operating system?
2. Compare containers vs virtual machines.

Daily Quiz Challenge

Frontend ( JavaScript ) :

1. What does typeof NaN return?
• 'undefined'
• 'number'
• 'NaN'>/
• 'object'
2. What will console.log(0.1 + 0.2 == 0.3) output?
• true
• false
3. Which of the following is a valid way to declare a variable?
• let x = 10;
• var x = 10;
• const x = 10;
• All of the above

Backend ( C, C++, C# ) :

1. What does sizeof(char) return in C?
• 1
• 2
• 4
• Compiler dependent
2. In C++, which feature allows function overloading?
• Inheritance
• Polymorphism
• Encapsulation
• All of the above
3. In C#, what keyword is used to inherit a class?
• inherits
• extends
• base
• :

Database ( SQL ) :

1. Which keyword is used to sort the result set?
• ORDER
• ORDERED
• ORDER BY
• SORT BY

Others :

1. What is the default port for HTTP?
• 443
• 21
• 80
• 25

Mixed Quiz :

1. Which of the following is not a primitive data type in JavaScript?
• string
• number
• boolean
• function

Weekly Cross-Domain Activities (Updated) ( May 16 to May 22, 2025 )

API of the Day:

Use the NASA Astronomy Picture of the Day (APOD) API

Challenge :

Build a mini web app that fetches and displays the daily astronomy picture from NASA's APOD API with its title and description.

• Challenge Add-on: Add a date picker to view past pictures.
• NASA APOD API Documentation

Linux/DevOps Tip :

Monitor Disk Usage with du and ncdu

Commands :

• Use du -sh * to get a summary of disk usage by folder.
• Use ncdu (if installed) for a more interactive and visual exploration of what's eating up space in your directories.

Real-World Project of the Week (Updated) ( May 16 to May 22, 2025 )

Project of the Week:

Build a Blog Platform with Markdown Support

• Use a backend like Node.js, Flask, or Django.
• Use a markdown parser (like marked in JS or markdown in Python) to render posts.
• Add support for categories, tags, and featured images.

Bonus : Allow login functionality to create/edit/delete posts.

Collaborative Project:

Create a “Dev Tools Hub” Web App.

• A multi-tool app offering features like:
• JSON formatter
• UUID generator
• Base64 encoder/decoder
• Regex tester
• Organize collaboration via GitHub and assign different tools to team members.

Case Study:

How Trello Works — Kanban Task Boards.

• Study how Trello organizes cards, lists, and boards.
• Build a mini Kanban board with drag-and-drop functionality using Sortable.js or native drag-and-drop API.
• Focus on data modeling and client-server sync logic.