Daily Coding Challenges & Projects

Frontend Mini Project Challenge

JavaScript Logic

Task :

Create a "Math Puzzle Solver" in JavaScript

Challenge :

• Allow users to input expressions like "3 + 5 * 2"
• Parse and evaluate using operator precedence
• Constraint : No use of eval()

Bonus : Add keyboard support for input

Backend Challenge

C, C++, C#

Language Focus : C++

Challenge : Implement a fixed-size circular queue class in C++

Task :

• Include enqueue, dequeue, peek, isFull, and isEmpty methods
• Test it with at least 10 enqueue/dequeue operations

Database Query Challenge

Problems on SQL - HR Database :

1. Write a SQL query to retrieve the top 3 departments with the highest average salary.
2. Write a SQL query to list employees whose hire date is the same as their manager’s hire date.

Data Structures & Algorithms Challenge

• Easy:
• Problem : Check if a given string is a palindrome (ignoring spaces and punctuation).
• Hint : Normalize the string before comparing with its reverse.
• Medium:
• Problem : Given a rotated sorted array, find the index of the minimum element.
• Hint : Use binary search logic adapted to rotated arrays.
• Hard:
• Problem : Given a string and a dictionary of words, segment the string into space-separated sequence of dictionary words.
• Hint : Use dynamic programming (word break problem).

Bug of the Day

C, C++, C#

Language : C Bug

Buggy Code:

#include 
int main() {
    int i = 5;
    if (i = 10) {
        printf("Value is 10");
    } else {
        printf("Value is not 10");
    }
    return 0;
}

Challenge : What’s wrong with this code? Fix it so it works as expected.

📋 Daily Micro-Project

Frontend Focus :

Project :

Build a dynamic "Time Converter" (Local ↔ UTC ↔ GMT) using JavaScript

• Auto-detect user’s time zone
• Convert input time to other zones

Bonus : Add date support

Trivia: 5 Fun Facts

1. C was developed by Dennis Ritchie at Bell Labs in 1972.
2. C++ was originally named "C with Classes".
3. JavaScript was created in just 10 days by Brendan Eich.
4. C# was developed by Microsoft under the .NET initiative.
5. First-ever computer bug was a moth trapped in a relay.

Tool & Resource of the Day

Tool : JSFiddle

A live online JavaScript editor to test snippets in real-time.

Resource Roundup

JavaScript Debugging Bundle

• MDN JavaScript Console Guide
• JavaScript Debugging Tips – FreeCodeCamp Video
• Awesome JavaScript Repos – GitHub

Interview Question of the Day

Daily Interview Questions

Frontend :
1. What are closures in JavaScript and why are they useful?
2. How does setTimeout() work under the hood?
3. Explain the concept of hoisting in JavaScript.
4. What is event bubbling and how can it be stopped?

Backend :
1. What is a segmentation fault in C/C++?
2. How does memory allocation differ in stack vs heap?
3. What are pointers in C and how are they used?
4. Explain constructor overloading in C#.

Database ( SQL ) :
1. How do GROUP BY and HAVING differ?
2. What is a composite primary key?
3. Explain normalization and its types.

Others :
1. What is the difference between a compiler and an interpreter?
2. What is a virtual machine (VM) in the context of programming?

Daily Quiz Challenge

Frontend Quiz ( JavaScript ) :

1. What is the output of console.log(typeof NaN);?
2. Which method removes the first element of an array in JavaScript?
3. What’s the difference between let and var?

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

1. What does the new keyword do in C#?
2. Which C++ operator is used to allocate memory dynamically?
3. What is the output of sizeof(char) in C?

Database :

1. Which SQL keyword is used to ensure unique column values?

Other :

1. Which layer of the OSI model does HTTP belong to?

Mixed Quiz :

1. JavaScript: What is a callback function?
2. SQL: How do you select the first 5 rows of a table?
3. C: What’s wrong with using gets() for input?

Weekly Cross-Domain Activities ( June 13 to June 19, 2025 )

API of the Day:

OpenWeatherMap API :

Use the REST Countries API

Task : Build a React app that lets users search a country and shows its flag, capital, and region.

Linux/DevOps Tip :

Top 5 Linux commands for server monitoring:

• top
• htop
• vmstat
• iotop
• netstat -tulpn

Real-World Project of the Week ( June 13 to June 19, 2025 )

Project of the Week:

Build a Task Manager App (Frontend + Backend + DB)

• Use React for UI
• Node.js + Express for API
• PostgreSQL for data persistence

Collaborative Project:

Contribute to the open-source Habit Tracker project on GitHub: github.com/codecrafters-io/habit-tracker.

Case Study:

How Notion Manages Real-Time Collaboration:

• WebSockets, Operational Transform (OT), and React for UI syncing.

Try replicating a collaborative notes editor using Firebase Realtime DB