JavaScript – Part 3: Exercises (Practice Guide + Concepts)

This is a structured JavaScript practice chapter focused on real coding exercises, logic building, and problem-solving. If you complete these exercises properly, you will move from beginner → solid intermediate level.

🧠 1. Variables, Data Types & Input Practice

JavaScript starts with understanding how data is stored and used.

🟢 Exercise 1: Personal Info Logger

Create variables for:

Your name
Age
Country
Favorite programming language

Then display them in console.

Task:

Use let or const
Print output using console.log()

Example:

let name = "Ali";
let age = 18;
let country = "Pakistan";
let language = "JavaScript";

console.log(name);
console.log(age);
console.log(country);
console.log(language);

🔥 Challenge:

Combine all values into one sentence:

"My name is Ali and I am 18 years old from Pakistan."

🟢 Exercise 2: Simple User Input Simulation

Since browser input is limited, simulate user data:

let username = "Zabi";
let email = "zabi@example.com";

Task:

Print a formatted profile card in console

Output style:

--- USER PROFILE ---
Name: Zabi
Email: zabi@example.com
--------------------

🔁 2. Conditions (if / else logic)

Conditions are the brain of programming.

🟡 Exercise 3: Even or Odd Checker

Task:

Create a number and check if it is even or odd.

let number = 10;

if (number % 2 === 0) {
  console.log("Even Number");
} else {
  console.log("Odd Number");
}

🔥 Challenge:

Modify it to check numbers up to 100.

🟡 Exercise 4: Age Verification System

Task:

Check if user is eligible for driving license.

Rules:

18+ → Allowed
Below 18 → Not allowed

let age = 17;

if (age >= 18) {
  console.log("You are eligible for driving.");
} else {
  console.log("You are not eligible yet.");
}

🟡 Exercise 5: Grade Calculator

Task:

Based on marks, assign grade:

90–100 → A+
80–89 → A
70–79 → B
60–69 → C
Below 60 → Fail

let marks = 85;

if (marks >= 90) {
  console.log("A+");
} else if (marks >= 80) {
  console.log("A");
} else if (marks >= 70) {
  console.log("B");
} else if (marks >= 60) {
  console.log("C");
} else {
  console.log("Fail");
}

🔁 3. Loops (Very Important for Logic Building)

Loops help repeat tasks efficiently.

🟠 Exercise 6: Print Numbers 1 to 10

for (let i = 1; i <= 10; i++) {
  console.log(i);
}

🟠 Exercise 7: Multiplication Table

Task:

Print table of 5.

let num = 5;

for (let i = 1; i <= 10; i++) {
  console.log(num + " x " + i + " = " + (num * i));
}

🟠 Exercise 8: Sum of Numbers

Task:

Find sum of 1 to 100.

let sum = 0;

for (let i = 1; i <= 100; i++) {
  sum = sum + i;
}

console.log(sum);

🟠 Exercise 9: Reverse Counting

for (let i = 10; i >= 1; i--) {
  console.log(i);
}

🧩 4. Functions (Reusable Logic)

Functions are reusable blocks of code.

🔵 Exercise 10: Simple Greeting Function

function greet(name) {
  console.log("Hello " + name);
}

greet("Ali");
greet("Zabi");

🔵 Exercise 11: Add Two Numbers

function add(a, b) {
  return a + b;
}

console.log(add(5, 10));

🔵 Exercise 12: Calculator Function

function calculator(a, b, operator) {
  if (operator === "+") return a + b;
  if (operator === "-") return a - b;
  if (operator === "*") return a * b;
  if (operator === "/") return a / b;
}

console.log(calculator(10, 5, "+"));

🧱 5. Arrays (Data Collections)

Arrays store multiple values.

🟣 Exercise 13: Array Basics

let fruits = ["Apple", "Banana", "Mango"];

console.log(fruits[0]);
console.log(fruits[1]);
console.log(fruits[2]);

🟣 Exercise 14: Loop Through Array

for (let i = 0; i < fruits.length; i++) {
  console.log(fruits[i]);
}

🟣 Exercise 15: Find Largest Number

let numbers = [10, 50, 30, 90, 20];

let max = numbers[0];

for (let i = 1; i < numbers.length; i++) {
  if (numbers[i] > max) {
    max = numbers[i];
  }
}

console.log("Largest:", max);

🧠 6. Mini Projects (Real Practice)

🟢 Project 1: Simple Login System

let username = "admin";
let password = "1234";

if (username === "admin" && password === "1234") {
  console.log("Login Successful");
} else {
  console.log("Login Failed");
}

🟢 Project 2: Number Guessing Game

let secret = 7;
let guess = 5;

if (guess === secret) {
  console.log("Correct!");
} else {
  console.log("Try Again!");
}

🟢 Project 3: Shopping Bill Calculator

let price1 = 100;
let price2 = 200;
let price3 = 150;

let total = price1 + price2 + price3;

console.log("Total Bill:", total);

🚀 FINAL PRACTICE CHALLENGE (IMPORTANT)

Create a program that:

takes a number
checks if it is even or odd
prints multiplication table
calculates sum up to that number

If you can do this, you are already intermediate level JavaScript developer.

🧠 WHAT YOU LEARNED

You practiced:

✔ Variables

✔ Conditions

✔ Loops

✔ Functions

✔ Arrays

✔ Mini projects