Daily Coding Challenges & Projects

Frontend Mini Project Challenge

Theme : JS Logical Puzzles / Debugging

Challenge :

Write a JavaScript function that checks whether a given string has balanced parentheses.

Example :

• "(()())" → ✅ Balanced
• "(()" → ❌ Not Balanced

Bonus : Extend it to check {}, [] along with ().

function isBalanced(str) {
  // Your code here
}

Try it online : CodePen / JSFiddle

Backend Challenge

Category : C, C++, C#

Challenge :

C : Write a program to reverse a string using pointers (no built-in string library functions).

C++ : Implement a class BankAccount with deposit, withdraw, and balance check methods. Add exception handling for insufficient balance.

C# : Create a console app that connects to a SQL Server database and retrieves all rows from an Employees table.

Database Query Challenge

Problems on SQL - HR Database :

1. Write a query to list employees who earn more than the average salary of their department.
2. Write a query to fetch the top 3 highest-paid employees in each department.

Data Structures & Algorithms Challenge

• Easy:
• Problem :Implement a function to reverse an array.
• Hint :Use two-pointer swapping.
• Medium:
• Problem : Implement a stack using two queues.
• Hint :Think about push vs. pop complexity.
• Hard:
• Problem :Given a graph, implement a function to detect if there is a cycle using DFS.

Bug of the Day

Language : C, C++, C#

Buggy Code ( C ):

#include <stdio.h>
int main() {
    char str[5];
    scanf("%s", str);
    printf("%s", str);
    return 0;
}

Challenge : Find and fix the error. (Hint: Think about buffer overflow when input > 4 chars.)

📋 Daily Micro-Project

Type : Frontend

Task :

Build a CSS-only toggle switch (like an ON/OFF button).

Trivia: 5 Fun Facts

1. The first computer bug was literally a moth, found in a Harvard Mark II in 1947.
2. Java was originally called Oak.
3. The C language was created at Bell Labs by Dennis Ritchie.
4. Git was developed by Linus Torvalds in 2005.
5. The first website ever built is still online: info.cern.ch.

Tool & Resource of the Day

Tool : Figma

Use : Collaborative design tool for UI/UX.

Resource Roundup :

• Figma Crash Course (YouTube)
• Free UI Kits on Figma Community
• "Design Better" eBook series

Interview Question of the Day

Daily Interview Questions

Frontend :
1. What are closures in JavaScript? Give an example.
2. Explain the difference between == and === in JavaScript.
3. What are controlled vs. uncontrolled components in React?
4. How do Vue.js lifecycle hooks work?

Backend :
1. What are memory leaks in C++ and how do you prevent them?
2. Explain the difference between abstract class and interface in C#.
3. How does garbage collection work in Java?
4. What are threads in C, and how are they created (POSIX threads)?

Database :
1. What is a correlated subquery?
2. What is the difference between UNION and UNION ALL?
3. Explain clustered vs. non-clustered indexes.

Others :
1. What is an operating system kernel?
2. Explain virtualization vs. containerization.

Daily Quiz Challenge

Frontend ) :

1. What is the output?

console.log(typeof NaN);

• number
• NaN
• undefined
• object
2. Which CSS property is used to make text bold?
• font-style
• font-weight
• text-decoration
• font-variant
3. In React, which hook is used for side effects?
• useState
• useEffect
• useContext
• useReducer

Backend :

1. In C, which header is needed for malloc()?
• stdio.h
• string.h
• stdlib.h
• malloc.h
2. In C#, which keyword is used to handle exceptions?
• try
• throw
• catch
• finally
3. Which OOP concept allows multiple functions with the same name but different parameters?
• Encapsulation
• Inheritance
• Polymorphism
• Abstraction

Mixed :

1. Database : Which SQL keyword is used to sort the results?
• SORT
• ORDER BY
• GROUP BY
• ARRANGE
2. Other : Who created the Python programming language?
• Guido van Rossum
• James Gosling
• Brendan Eich
• Dennis Ritchie

Weekly Cross-Domain Activities ( August 15 to August 21, 2025 )

API of the Day:

Build a currency converter using the ExchangeRate API

Real-World Project of the Week ( August 15 to August 21, 2025 )

Project of the Week:

Idea : Build a personal expense tracker

• Frontend : React + Tailwind CSS
• Backend : Node.js + Express + MongoDB
• Features : Add, edit, delete expenses; filter by date and category; show monthly summaries.