Coding interview questions with concise answers for software roles:

1️⃣ What happens when you type a URL and hit Enter?
Answer:
- DNS Lookup → IP address
- Browser sends HTTP/HTTPS request
- Server responds with HTML/CSS/JS
- Browser builds DOM, applies styles (CSSOM), runs JS
- Page is rendered


2️⃣ Difference between var, let, and const?
Answer:
- var: function-scoped, hoisted
- let: block-scoped, not hoisted
- const: block-scoped, can’t be reassigned


3️⃣ Reverse a String in JavaScript

function reverseString(str) {
  return str.split('').reverse().join('');
}

4️⃣ Find the max number in an array

const max = Math.max(...arr);

5️⃣ Write a function to check if a number is prime

function isPrime(n) {
  if (n < 2) return false;
  for (let i = 2; i <= Math.sqrt(n); i++) {
    if (n % i === 0) return false;
  }
  return true;
}

6️⃣ What is closure in JavaScript?
Answer:
A function that remembers variables from its outer scope even after the outer function has returned.

7️⃣ What is event delegation?
Answer:
Attaching a single event listener to a parent element to manage events on its children using event.target.

8️⃣ Difference between == and ===
Answer:
- == checks value (with type coercion)
- === checks value + type (strict comparison)

9️⃣ What is the Virtual DOM?
Answer:
A lightweight copy of the real DOM used in React. React updates the virtual DOM first and then applies only the changes to the real DOM for efficiency.

🔟 Write code to remove duplicates from an array

const uniqueArr = [...new Set(arr)];

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✅ 10 Key Programming Differences! 💻🚀

1️⃣ Python 2 vs Python 3
➡️ Python 2: Legacy, no updates
➡️ Python 3: Modern, better syntax support
📌 Always use Python 3 for new projects.

2️⃣ Static vs Dynamic Typing
➡️ Static: Type declared (e.g., Java, C++)
➡️ Dynamic: Type inferred at runtime (e.g., Python, JavaScript)
📌 Static = fewer bugs, Dynamic = faster dev

3️⃣ Abstraction vs Encapsulation
➡️ Abstraction: Hides complexity
➡️ Encapsulation: Hides data
📌 Abstraction = "What", Encapsulation = "How"

4️⃣ REST vs SOAP (APIs)
➡️ REST: Lightweight, uses HTTP
➡️ SOAP: Protocol, strict rules
📌 REST is more common today

5️⃣ SQL vs NoSQL
➡️ SQL: Structured data, tables (e.g., MySQL)
➡️ NoSQL: Unstructured, scalable (e.g., MongoDB)
📌 SQL = Relational, NoSQL = Flexible

6️⃣ For Loop vs While Loop
➡️ For: Known iterations
➡️ While: Unknown, condition-based
📌 Use for when count is known.

7️⃣ Function vs Method
➡️ Function: Independent block
➡️ Method: Function inside class
📌 All methods are functions, not vice versa

8️⃣ Frontend vs Backend
➡️ Frontend: User interface (HTML, CSS, JS)
➡️ Backend: Server logic, DB (Node.js, Python, etc.)
📌 Frontend = what users see

9️⃣ Procedural vs OOP
➡️ Procedural: Functions logic
➡️ OOP: Objects, classes
📌 OOP = more modular reusable

🔟 Null vs Undefined (JavaScript)
➡️ Null: Assigned empty value
➡️ Undefined: Variable declared, not assigned
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