# Create a new React Native project for learning
npx react-native init JSFoundationsLearning

# Navigate to the project
cd JSFoundationsLearning

# Create our learning folders
mkdir src
mkdir src/01-variables
mkdir src/02-datatypes
mkdir src/03-operators
mkdir src/04-controlflow
mkdir src/05-loops
mkdir src/06-arrays

// src/test.js
console.log("Hello, JavaScript learner!");
console.log("Your React Native environment is ready!");

// App.js
import React from 'react';
import {View, Text} from 'react-native';

// Import your test file (this will run the console.log statements)
import './src/test.js';

const App = () => {
  return (
    <View style={{flex: 1, justifyContent: 'center', alignItems: 'center'}}>
      <Text>Check your terminal for JavaScript output!</Text>
    </View>
  );
};

export default App;

# For Android
npx react-native run-android

# For iOS
npx react-native run-ios

// src/01-variables/variables.js
console.log("=== VARIABLES LESSON ===");

// Three ways to declare variables in modern JavaScript
let userName = "Alex";
const appName = "MyAwesomeApp";
var oldStyleVariable = "Don't use this much";

console.log("User name:", userName);
console.log("App name:", appName);
console.log("Old style:", oldStyleVariable);

// App.js
import React from 'react';
import {View, Text} from 'react-native';

// Import your variables lesson
import './src/01-variables/variables.js';

const App = () => {
  return (
    <View style={{flex: 1, justifyContent: 'center', alignItems: 'center'}}>
      <Text>Variables Lesson - Check Terminal!</Text>
    </View>
  );
};

export default App;

// src/01-variables/keywords.js
console.log("=== VARIABLE KEYWORDS ===");

// const - Cannot be reassigned
const pi = 3.14159;
console.log("Pi value:", pi);

// This would cause an error:
// pi = 3.14; // TypeError: Assignment to constant variable

// let - Can be reassigned
let score = 100;
console.log("Initial score:", score);
score = 150; // This is fine
console.log("Updated score:", score);

// var - Old way, has weird behavior
var message = "Hello";
console.log("Message:", message);
var message = "Hi"; // This doesn't cause an error, but it's confusing
console.log("Changed message:", message);

// src/01-variables/naming.js
console.log("=== VARIABLE NAMING ===");

// Good naming practices
const firstName = "John";           // camelCase - recommended
const userAge = 25;                 // descriptive
const isLoggedIn = true;            // boolean starts with 'is'
const MAX_RETRIES = 3;              // constants in UPPER_CASE

// What NOT to do
// let 123abc = "bad";              // Can't start with number
// let user-name = "bad";           // Can't use hyphens
// let let = "bad";                 // Can't use reserved words

console.log("First name:", firstName);
console.log("User age:", userAge);
console.log("Is logged in:", isLoggedIn);
console.log("Max retries:", MAX_RETRIES);

// src/01-variables/exercise1.js
console.log("=== EXERCISE 1: Personal Information ===");

// Store your information in variables
const myName = "Your Name Here";
let myAge = 25;
let favoriteColor = "blue";
const birthYear = 1998;

// Display the information
console.log("Name:", myName);
console.log("Age:", myAge);
console.log("Favorite color:", favoriteColor);
console.log("Birth year:", birthYear);

// Try changing some values
myAge = 26; // This should work
favoriteColor = "green"; // This should work
console.log("Updated age:", myAge);
console.log("Updated favorite color:", favoriteColor);

// Challenge: Try to change myName or birthYear
// (This should cause an error because they're const)

// src/02-datatypes/primitives.js
console.log("=== PRIMITIVE DATA TYPES ===");

// String - Text information
const userName = "Jessica";
const message = 'Hello, world!';
const templateString = `Welcome, ${userName}!`;

console.log("String examples:");
console.log(userName);
console.log(message);
console.log(templateString);

// Number - Both integers and decimals
const age = 28;
const price = 19.99;
const negative = -5;

console.log("Number examples:");
console.log("Age:", age);
console.log("Price:", price);
console.log("Negative:", negative);

// Boolean - True or false
const isActive = true;
const isComplete = false;

console.log("Boolean examples:");
console.log("Is active:", isActive);
console.log("Is complete:", isComplete);

// Undefined - Variable declared but not assigned
let notAssigned;
console.log("Undefined example:", notAssigned);

// Null - Intentionally empty
const emptyValue = null;
console.log("Null example:", emptyValue);

// src/02-datatypes/strings.js
console.log("=== STRING OPERATIONS ===");

const firstName = "John";
const lastName = "Doe";

// String concatenation (joining strings)
const fullName = firstName + " " + lastName;
console.log("Full name:", fullName);

// Template literals (modern way)
const greeting = `Hello, ${firstName}! How are you?`;
console.log("Greeting:", greeting);

// String properties and methods
console.log("Name length:", fullName.length);
console.log("Uppercase:", fullName.toUpperCase());
console.log("Lowercase:", fullName.toLowerCase());

// String methods you'll use often
const email = "  user@example.com  ";
console.log("Original email:", email);
console.log("Trimmed email:", email.trim());
console.log("Includes @:", email.includes("@"));

// src/02-datatypes/numbers.js
console.log("=== NUMBER OPERATIONS ===");

const a = 10;
const b = 3;

// Basic math operations
console.log("Addition:", a + b);
console.log("Subtraction:", a - b);
console.log("Multiplication:", a * b);
console.log("Division:", a / b);
console.log("Remainder:", a % b);

// Special number methods
const decimal = 3.14159;
console.log("Rounded:", Math.round(decimal));
console.log("Rounded up:", Math.ceil(decimal));
console.log("Rounded down:", Math.floor(decimal));

// Converting strings to numbers
const userInput = "25";
const convertedNumber = Number(userInput);
console.log("Original:", userInput, "Type:", typeof userInput);
console.log("Converted:", convertedNumber, "Type:", typeof convertedNumber);

// src/02-datatypes/typeof.js
console.log("=== TYPE CHECKING ===");

const examples = [
  "Hello",
  42,
  true,
  null,
  undefined,
  { name: "John" },
  [1, 2, 3]
];

// Check the type of each example
examples.forEach((example, index) => {
  console.log(`Example ${index + 1}:`, example, "Type:", typeof example);
});

// Practical type checking
function checkUserInput(input) {
  if (typeof input === 'string') {
    console.log("Processing text:", input);
  } else if (typeof input === 'number') {
    console.log("Processing number:", input);
  } else if (typeof input === 'boolean') {
    console.log("Processing boolean:", input);
  } else {
    console.log("Unknown type:", typeof input);
  }
}

checkUserInput("Hello");
checkUserInput(42);
checkUserInput(true);

// src/02-datatypes/exercise2.js
console.log("=== EXERCISE 2: Data Types Practice ===");

// Create variables of different types
const movieTitle = "The Matrix";
const releaseYear = 1999;
const rating = 8.7;
const isClassic = true;
const director = null; // We'll assign this later

// Display information about the movie
console.log("Movie Information:");
console.log("Title:", movieTitle, "(Type:", typeof movieTitle + ")");
console.log("Release Year:", releaseYear, "(Type:", typeof releaseYear + ")");
console.log("Rating:", rating, "(Type:", typeof rating + ")");
console.log("Is Classic:", isClassic, "(Type:", typeof isClassic + ")");
console.log("Director:", director, "(Type:", typeof director + ")");

// String manipulation
const description = `${movieTitle} is a ${isClassic ? 'classic' : 'modern'} movie from ${releaseYear}`;
console.log("Description:", description);

// Number operations
const ageOfMovie = 2024 - releaseYear;
console.log("Age of movie:", ageOfMovie, "years");

// Challenge: Create a movie review summary
const reviewSummary = `"${movieTitle}" (${releaseYear}) - Rating: ${rating}/10`;
console.log("Review Summary:", reviewSummary);

// src/03-operators/arithmetic.js
console.log("=== ARITHMETIC OPERATORS ===");

const a = 15;
const b = 4;

// Basic arithmetic
console.log("Addition (a + b):", a + b);           // 19
console.log("Subtraction (a - b):", a - b);        // 11
console.log("Multiplication (a * b):", a * b);     // 60
console.log("Division (a / b):", a / b);           // 3.75
console.log("Remainder (a % b):", a % b);          // 3

// Increment and decrement
let counter = 10;
console.log("Original counter:", counter);
counter++; // Same as counter = counter + 1
console.log("After increment:", counter);
counter--; // Same as counter = counter - 1
console.log("After decrement:", counter);

// Exponentiation (power)
console.log("2 to the power of 3:", 2 ** 3);       // 8

// src/03-operators/assignment.js
console.log("=== ASSIGNMENT OPERATORS ===");

let score = 100;
console.log("Initial score:", score);

// Basic assignment
score = 150;
console.log("New score:", score);

// Compound assignment operators
score += 50;    // Same as: score = score + 50
console.log("After += 50:", score);

score -= 25;    // Same as: score = score - 25
console.log("After -= 25:", score);

score *= 2;     // Same as: score = score * 2
console.log("After *= 2:", score);

score /= 5;     // Same as: score = score / 5
console.log("After /= 5:", score);

// String concatenation assignment
let message = "Hello";
message += " World";    // Same as: message = message + " World"
console.log("Message:", message);

// src/03-operators/comparison.js
console.log("=== COMPARISON OPERATORS ===");

const age = 25;
const requiredAge = 18;
const userInput = "25";

// Equality comparisons
console.log("age == requiredAge:", age == requiredAge);     // false
console.log("age === 25:", age === 25);                    // true
console.log("age == userInput:", age == userInput);        // true (type coercion)
console.log("age === userInput:", age === userInput);      // false (strict comparison)

// Inequality comparisons
console.log("age != requiredAge:", age != requiredAge);    // true
console.log("age !== userInput:", age !== userInput);     // true

// Relational comparisons
console.log("age > requiredAge:", age > requiredAge);      // true
console.log("age < requiredAge:", age < requiredAge);      // false
console.log("age >= 25:", age >= 25);                     // true
console.log("age <= 30:", age <= 30);                     // true

// Important difference between == and ===
console.log("'5' == 5:", '5' == 5);                      // true (converts string to number)
console.log("'5' === 5:", '5' === 5);                    // false (different types)

// src/03-operators/logical.js
console.log("=== LOGICAL OPERATORS ===");

const isLoggedIn = true;
const hasPermission = false;
const isAdmin = true;
const age = 25;

// AND operator (&&) - both conditions must be true
console.log("Logged in AND has permission:", isLoggedIn && hasPermission);
console.log("Logged in AND is admin:", isLoggedIn && isAdmin);

// OR operator (||) - at least one condition must be true
console.log("Has permission OR is admin:", hasPermission || isAdmin);
console.log("Age > 18 OR is admin:", age > 18 || isAdmin);

// NOT operator (!) - reverses the boolean value
console.log("NOT logged in:", !isLoggedIn);
console.log("NOT has permission:", !hasPermission);

// Practical examples
const canAccessAdminPanel = isLoggedIn && isAdmin;
const canViewContent = isLoggedIn || age > 18;
const needsLogin = !isLoggedIn;

console.log("Can access admin panel:", canAccessAdminPanel);
console.log("Can view content:", canViewContent);
console.log("Needs login:", needsLogin);

// src/03-operators/exercise3.js
console.log("=== EXERCISE 3: Calculator Practice ===");

// Create a simple calculator
const num1 = 20;
const num2 = 8;

console.log("Calculator Input:");
console.log("First number:", num1);
console.log("Second number:", num2);
console.log("---");

// Perform all operations
console.log("Addition:", num1 + num2);
console.log("Subtraction:", num1 - num2);
console.log("Multiplication:", num1 * num2);
console.log("Division:", num1 / num2);
console.log("Remainder:", num1 % num2);
console.log("Power:", num1 ** num2);

// Comparison practice
console.log("---");
console.log("Comparison Results:");
console.log("num1 > num2:", num1 > num2);
console.log("num1 === num2:", num1 === num2);
console.log("num1 >= 20:", num1 >= 20);

// Logical operations
const isPositive1 = num1 > 0;
const isPositive2 = num2 > 0;
const isEven1 = num1 % 2 === 0;
const isEven2 = num2 % 2 === 0;

console.log("---");
console.log("Logical Results:");
console.log("Both numbers positive:", isPositive1 && isPositive2);
console.log("At least one even:", isEven1 || isEven2);
console.log("First number not even:", !isEven1);

// src/04-controlflow/if-statements.js
console.log("=== IF STATEMENTS ===");

const age = 20;
const hasLicense = true;

// Simple if statement
if (age >= 18) {
  console.log("You are an adult!");
}

// If-else statement
if (hasLicense) {
  console.log("You can drive!");
} else {
  console.log("You need a license to drive.");
}

// If-else if-else chain
const score = 85;

if (score >= 90) {
  console.log("Grade: A");
} else if (score >= 80) {
  console.log("Grade: B");
} else if (score >= 70) {
  console.log("Grade: C");
} else if (score >= 60) {
  console.log("Grade: D");
} else {
  console.log("Grade: F");
}

// Complex conditions
const isWeekend = true;
const weather = "sunny";

if (isWeekend && weather === "sunny") {
  console.log("Perfect day for a picnic!");
} else if (isWeekend && weather === "rainy") {
  console.log("Good day to stay inside and read.");
} else {
  console.log("It's a regular day.");
}

// src/04-controlflow/switch-statements.js
console.log("=== SWITCH STATEMENTS ===");

const dayOfWeek = 3;

switch (dayOfWeek) {
  case 1:
    console.log("Monday - Start of the work week");
    break;
  case 2:
    console.log("Tuesday - Getting into the groove");
    break;
  case 3:
    console.log("Wednesday - Hump day!");
    break;
  case 4:
    console.log("Thursday - Almost there");
    break;
  case 5:
    console.log("Friday - TGIF!");
    break;
  case 6:
  case 7:
    console.log("Weekend - Time to relax!");
    break;
  default:
    console.log("Invalid day");
}

// Switch with strings
const userRole = "admin";

switch (userRole) {
  case "admin":
    console.log("Full access granted");
    break;
  case "moderator":
    console.log("Limited administrative access");
    break;
  case "user":
    console.log("Standard user access");
    break;
  default:
    console.log("Unknown role");
}

// src/04-controlflow/ternary.js
console.log("=== TERNARY OPERATOR ===");

const temperature = 25;

// Instead of:
// if (temperature > 20) {
//   console.log("It's warm");
// } else {
//   console.log("It's cool");
// }

// You can write:
const weatherDescription = temperature > 20 ? "It's warm" : "It's cool";
console.log(weatherDescription);

// Multiple ternary operators
const age = 17;
const status = age >= 18 ? "adult" : age >= 13 ? "teenager" : "child";
console.log("Status:", status);

// Practical example
const isLoggedIn = true;
const username = "john_doe";

const greeting = isLoggedIn ? `Welcome back, ${username}!` : "Please log in";
console.log(greeting);

// src/04-controlflow/exercise4.js
console.log("=== EXERCISE 4: User Authentication System ===");

// Simulate user data
const username = "john_doe";
const password = "secret123";
const userRole = "admin";
const isAccountActive = true;

// Authentication check
console.log("Authentication System");
console.log("---");

if (username === "john_doe" && password === "secret123") {
  console.log("✅ Username and password correct");

  if (isAccountActive) {
    console.log("✅ Account is active");

    // Check user role and grant appropriate access
    switch (userRole) {
      case "admin":
        console.log("🔑 Admin access granted - Full control");
        break;
      case "moderator":
        console.log("🔑 Moderator access granted - Limited control");
        break;
      case "user":
        console.log("🔑 User access granted - Standard features");
        break;
      default:
        console.log("❌ Unknown role - Access denied");
    }
  } else {
    console.log("❌ Account is inactive - Contact administrator");
  }
} else {
  console.log("❌ Invalid username or password");
}

// Bonus: Age verification system
const userAge = 20;
const hasParentalConsent = false;

const accessLevel = userAge >= 18 ? "full" : hasParentalConsent ? "limited" : "restricted";
console.log("---");
console.log("Age verification result:", accessLevel);

// src/05-loops/for-loops.js
console.log("=== FOR LOOPS ===");

// Basic for loop structure
console.log("Counting from 1 to 5:");
for (let i = 1; i <= 5; i++) {
  console.log("Count:", i);
}

// Counting backwards
console.log("Countdown:");
for (let i = 5; i >= 1; i--) {
  console.log("T-minus", i);
}
console.log("Blast off! 🚀");

// Skip counting
console.log("Even numbers from 2 to 10:");
for (let i = 2; i <= 10; i += 2) {
  console.log("Even number:", i);
}

// Practical example: Processing a list
const fruits = ["apple", "banana", "orange", "grape"];
console.log("Fruits in my basket:");
for (let i = 0; i < fruits.length; i++) {
  console.log(`${i + 1}. ${fruits[i]}`);
}

// src/05-loops/while-loops.js
console.log("=== WHILE LOOPS ===");

// Basic while loop
let count = 1;
console.log("Counting with while loop:");
while (count <= 5) {
  console.log("Count:", count);
  count++; // Don't forget to increment!
}

// Practical example: Finding a number
let number = 1;
console.log("Finding first number divisible by 7:");
while (number % 7 !== 0) {
  number++;
}
console.log("Found:", number);

// Do-while loop (executes at least once)
let userInput;
let attempts = 0;
console.log("Password validation simulation:");
do {
  attempts++;
  userInput = attempts === 1 ? "wrong" : attempts === 2 ? "also wrong" : "correct";
  console.log(`Attempt ${attempts}: ${userInput}`);
} while (userInput !== "correct" && attempts < 3);

if (userInput === "correct") {
  console.log("Access granted!");
} else {
  console.log("Too many attempts. Account locked.");
}

// src/05-loops/for-of-loops.js
console.log("=== FOR...OF LOOPS ===");

// Iterating over arrays
const colors = ["red", "green", "blue", "yellow"];
console.log("Colors in my palette:");
for (const color of colors) {
  console.log("Color:", color);
}

// Iterating over strings
const word = "JavaScript";
console.log("Letters in 'JavaScript':");
for (const letter of word) {
  console.log("Letter:", letter);
}

// Practical example: Shopping cart
const shoppingCart = ["laptop", "mouse", "keyboard", "monitor"];
let totalItems = 0;

console.log("Processing shopping cart:");
for (const item of shoppingCart) {
  totalItems++;
  console.log(`Processing item ${totalItems}: ${item}`);
}
console.log(`Total items processed: ${totalItems}`);

// src/05-loops/loop-control.js
console.log("=== LOOP CONTROL: BREAK AND CONTINUE ===");

// Using continue to skip
console.log("Odd numbers from 1 to 10:");
for (let i = 1; i <= 10; i++) {
  if (i % 2 === 0) {
    continue; // Skip even numbers
  }
  console.log("Odd number:", i);
}

// Using break to stop early
console.log("Looking for the number 7:");
for (let i = 1; i <= 10; i++) {
  if (i === 7) {
    console.log("Found 7! Stopping search.");
    break;
  }
  console.log("Checking:", i);
}

// Practical example: Finding first valid user
const users = ["", "invalid", "john_doe", "jane_smith", ""];
console.log("Finding first valid user:");
for (const user of users) {
  if (user === "") {
    console.log("Skipping empty user");
    continue;
  }
  if (user === "invalid") {
    console.log("Skipping invalid user");
    continue;
  }
  console.log("Found valid user:", user);
  break; // Stop after finding first valid user
}

// src/05-loops/exercise5.js
console.log("=== EXERCISE 5: Number Guessing Game ===");

// Simulate a number guessing game
const secretNumber = 7;
const maxAttempts = 5;

let attempts = 0;
let hasWon = false;

// Array of simulated guesses (in real game, these would come from user input)
const guesses = [3, 9, 5, 7, 2];

console.log("Welcome to the Number Guessing Game!");
console.log("I'm thinking of a number between 1 and 10.");
console.log(`You have ${maxAttempts} attempts to guess it.`);
console.log("---");

// Main game loop
while (attempts < maxAttempts && !hasWon) {
  attempts++;
  const currentGuess = guesses[attempts - 1];

  console.log(`Attempt ${attempts}: You guessed ${currentGuess}`);

  if (currentGuess === secretNumber) {
    console.log("🎉 Congratulations! You guessed the number!");
    hasWon = true;
  } else if (currentGuess < secretNumber) {
    console.log("Too low! Try a higher number.");
  } else {
    console.log("Too high! Try a lower number.");
  }

  // Show remaining attempts
  if (!hasWon && attempts < maxAttempts) {
    console.log(`You have ${maxAttempts - attempts} attempts left.`);
  }
  console.log("---");
}

// Game over message
if (!hasWon) {
  console.log(`Game Over! The number was ${secretNumber}.`);
  console.log("Better luck next time!");
}

// Bonus: Calculate success rate
const successRate = hasWon ? ((maxAttempts - attempts + 1) / maxAttempts * 100).toFixed(1) : 0;
console.log(`Success rate: ${successRate}%`);

// src/06-arrays/creating-arrays.js
console.log("=== CREATING AND ACCESSING ARRAYS ===");

// Different ways to create arrays
const fruits = ["apple", "banana", "orange"];
const numbers = [1, 2, 3, 4, 5];
const mixed = ["hello", 42, true, null];
const empty = [];

// Using Array constructor (less common)
const colors = new Array("red", "green", "blue");

console.log("Fruits array:", fruits);
console.log("Numbers array:", numbers);
console.log("Mixed array:", mixed);
console.log("Empty array:", empty);
console.log("Colors array:", colors);

// Accessing array elements (zero-based indexing)
console.log("First fruit:", fruits[0]);        // "apple"
console.log("Second fruit:", fruits[1]);       // "banana"
console.log("Last fruit:", fruits[2]);         // "orange"

// Array length property
console.log("Number of fruits:", fruits.length);

// Accessing last element dynamically
console.log("Last fruit (dynamic):", fruits[fruits.length - 1]);

// Trying to access non-existent index
console.log("Fourth fruit:", fruits[3]);       // undefined

// src/06-arrays/modifying-arrays.js
console.log("=== MODIFYING ARRAYS ===");

let shoppingList = ["milk", "bread"];
console.log("Initial shopping list:", shoppingList);

// Adding elements to the end
shoppingList.push("eggs");
shoppingList.push("cheese", "butter"); // Can add multiple items
console.log("After adding items:", shoppingList);

// Adding elements to the beginning
shoppingList.unshift("coffee");
console.log("After adding coffee to beginning:", shoppingList);

// Removing elements from the end
const removedItem = shoppingList.pop();
console.log("Removed item:", removedItem);
console.log("After removing last item:", shoppingList);

// Removing elements from the beginning
const firstItem = shoppingList.shift();
console.log("Removed first item:", firstItem);
console.log("After removing first item:", shoppingList);

// Removing elements from middle (splice method)
// splice(startIndex, deleteCount, ...itemsToAdd)
shoppingList.splice(1, 1, "organic bread", "almond milk");
console.log("After replacing bread with organic options:", shoppingList);

// Adding elements in the middle without removing
shoppingList.splice(2, 0, "yogurt");
console.log("After adding yogurt:", shoppingList);

// src/06-arrays/array-methods.js
console.log("=== ARRAY METHODS ===");

const numbers = [1, 2, 3, 4, 5];
const fruits = ["apple", "banana", "orange", "grape"];

// Finding elements
console.log("Finding 3 in numbers:", numbers.includes(3));        // true
console.log("Index of 'banana':", fruits.indexOf("banana"));     // 1
console.log("Index of 'kiwi':", fruits.indexOf("kiwi"));         // -1 (not found)

// Joining arrays into strings
console.log("Fruits as string:", fruits.join(", "));
console.log("Numbers with dashes:", numbers.join("-"));

// Slicing arrays (creates new array)
const someFruits = fruits.slice(1, 3);  // From index 1 to 2 (3 is excluded)
console.log("Some fruits:", someFruits);
console.log("Original fruits unchanged:", fruits);

// Concatenating arrays
const moreFruits = ["kiwi", "mango"];
const allFruits = fruits.concat(moreFruits);
console.log("All fruits:", allFruits);

// Reversing arrays (modifies original)
const reversedNumbers = [...numbers].reverse(); // Using spread to avoid modifying original
console.log("Reversed numbers:", reversedNumbers);
console.log("Original numbers:", numbers);

// Sorting arrays
const unsortedFruits = ["orange", "apple", "banana", "grape"];
const sortedFruits = [...unsortedFruits].sort();
console.log("Sorted fruits:", sortedFruits);

// Sorting numbers (requires compare function)
const unsortedNumbers = [10, 5, 40, 25, 1000, 1];
const sortedNumbers = [...unsortedNumbers].sort((a, b) => a - b);
console.log("Sorted numbers:", sortedNumbers);

// src/06-arrays/array-loops.js
console.log("=== LOOPING THROUGH ARRAYS ===");

const tasks = ["Write code", "Test application", "Debug issues", "Deploy app"];

// Method 1: Traditional for loop
console.log("Method 1: Traditional for loop");
for (let i = 0; i < tasks.length; i++) {
  console.log(`${i + 1}. ${tasks[i]}`);
}

// Method 2: for...of loop (modern and clean)
console.log("\nMethod 2: for...of loop");
for (const task of tasks) {
  console.log(`Task: ${task}`);
}

// Method 3: forEach method (functional approach)
console.log("\nMethod 3: forEach method");
tasks.forEach((task, index) => {
  console.log(`${index + 1}. ${task}`);
});

// Method 4: for...in loop (gets indices, not recommended for arrays)
console.log("\nMethod 4: for...in loop (indices)");
for (const index in tasks) {
  console.log(`Index ${index}: ${tasks[index]}`);
}

// Practical example: Processing user data
const users = [
  { name: "Alice", age: 25, active: true },
  { name: "Bob", age: 30, active: false },
  { name: "Charlie", age: 35, active: true }
];

console.log("\nProcessing user data:");
users.forEach(user => {
  const status = user.active ? "Active" : "Inactive";
  console.log(`${user.name} (${user.age} years old) - ${status}`);
});

// src/06-arrays/exercise6.js
console.log("=== EXERCISE 6: Student Grade Manager ===");

// Initialize student data
const students = ["Alice", "Bob", "Charlie", "Diana", "Eve"];
const grades = [85, 92, 78, 96, 88];

console.log("Student Grade Management System");
console.log("================================");

// Display all students and their grades
console.log("All Students and Grades:");
for (let i = 0; i < students.length; i++) {
  console.log(`${students[i]}: ${grades[i]}%`);
}

// Calculate class statistics
let totalGrades = 0;
let highestGrade = grades[0];
let lowestGrade = grades[0];
let highestStudent = students[0];
let lowestStudent = students[0];

for (let i = 0; i < grades.length; i++) {
  totalGrades += grades[i];

  if (grades[i] > highestGrade) {
    highestGrade = grades[i];
    highestStudent = students[i];
  }

  if (grades[i] < lowestGrade) {
    lowestGrade = grades[i];
    lowestStudent = students[i];
  }
}

const averageGrade = totalGrades / grades.length;

console.log("\nClass Statistics:");
console.log(`Average Grade: ${averageGrade.toFixed(1)}%`);
console.log(`Highest Grade: ${highestStudent} with ${highestGrade}%`);
console.log(`Lowest Grade: ${lowestStudent} with ${lowestGrade}%`);

// Categorize students by performance
const excellentStudents = [];
const goodStudents = [];
const needsImprovementStudents = [];

for (let i = 0; i < students.length; i++) {
  if (grades[i] >= 90) {
    excellentStudents.push(students[i]);
  } else if (grades[i] >= 80) {
    goodStudents.push(students[i]);
  } else {
    needsImprovementStudents.push(students[i]);
  }
}

console.log("\nPerformance Categories:");
console.log(`Excellent (90%+): ${excellentStudents.join(", ")}`);
console.log(`Good (80-89%): ${goodStudents.join(", ")}`);
console.log(`Needs Improvement (<80%): ${needsImprovementStudents.join(", ")}`);

// Add new student
const newStudent = "Frank";
const newGrade = 89;
students.push(newStudent);
grades.push(newGrade);

console.log(`\nAdded new student: ${newStudent} with grade ${newGrade}%`);
console.log(`Total students: ${students.length}`);

// Find students above average
const aboveAverageStudents = [];
for (let i = 0; i < students.length; i++) {
  if (grades[i] > averageGrade) {
    aboveAverageStudents.push(students[i]);
  }
}

console.log(`Students above average: ${aboveAverageStudents.join(", ")}`);

// src/practice-exercises/exercise7.js
console.log("=== EXERCISE 7: Personal Finance Tracker ===");

// Initialize financial data
const transactions = [
  { type: "income", amount: 3000, description: "Salary", date: "2024-01-01" },
  { type: "expense", amount: 1200, description: "Rent", date: "2024-01-02" },
  { type: "expense", amount: 300, description: "Groceries", date: "2024-01-03" },
  { type: "income", amount: 500, description: "Freelance", date: "2024-01-04" },
  { type: "expense", amount: 100, description: "Gas", date: "2024-01-05" },
  { type: "expense", amount: 200, description: "Utilities", date: "2024-01-06" }
];

console.log("Personal Finance Tracker");
console.log("========================");

// Display all transactions
console.log("All Transactions:");
transactions.forEach((transaction, index) => {
  const sign = transaction.type === "income" ? "+" : "-";
  console.log(`${index + 1}. ${transaction.date}: ${sign}$${transaction.amount} - ${transaction.description}`);
});

// Calculate totals
let totalIncome = 0;
let totalExpenses = 0;

for (const transaction of transactions) {
  if (transaction.type === "income") {
    totalIncome += transaction.amount;
  } else {
    totalExpenses += transaction.amount;
  }
}

const netBalance = totalIncome - totalExpenses;

console.log("\nFinancial Summary:");
console.log(`Total Income: $${totalIncome}`);
console.log(`Total Expenses: $${totalExpenses}`);
console.log(`Net Balance: $${netBalance}`);

// Budget analysis
const budgetLimit = 2000;
const remainingBudget = budgetLimit - totalExpenses;

console.log("\nBudget Analysis:");
console.log(`Budget Limit: $${budgetLimit}`);
console.log(`Remaining Budget: $${remainingBudget}`);

if (remainingBudget > 0) {
  console.log("✅ You're within budget!");
} else {
  console.log("❌ You've exceeded your budget!");
}

// Find largest expense
let largestExpense = 0;
let largestExpenseDescription = "";

for (const transaction of transactions) {
  if (transaction.type === "expense" && transaction.amount > largestExpense) {
    largestExpense = transaction.amount;
    largestExpenseDescription = transaction.description;
  }
}

console.log(`\nLargest Expense: $${largestExpense} for ${largestExpenseDescription}`);

// src/practice-exercises/exercise8.js
console.log("=== EXERCISE 8: Todo List Manager ===");

// Initialize todo list
const todos = [
  { id: 1, task: "Learn JavaScript", completed: false, priority: "high" },
  { id: 2, task: "Practice coding", completed: true, priority: "medium" },
  { id: 3, task: "Build React Native app", completed: false, priority: "high" },
  { id: 4, task: "Read documentation", completed: false, priority: "low" },
  { id: 5, task: "Exercise", completed: true, priority: "medium" }
];

console.log("Todo List Manager");
console.log("================");

// Display all todos
function displayTodos() {
  console.log("All Todos:");
  todos.forEach(todo => {
    const status = todo.completed ? "✅" : "❌";
    const priority = todo.priority.toUpperCase();
    console.log(`${status} [${priority}] ${todo.task}`);
  });
}

displayTodos();

// Count completed and pending todos
let completedCount = 0;
let pendingCount = 0;

for (const todo of todos) {
  if (todo.completed) {
    completedCount++;
  } else {
    pendingCount++;
  }
}

console.log(`\nProgress: ${completedCount} completed, ${pendingCount} pending`);

// Display pending todos by priority
const highPriorityTodos = [];
const mediumPriorityTodos = [];
const lowPriorityTodos = [];

for (const todo of todos) {
  if (!todo.completed) {
    switch (todo.priority) {
      case "high":
        highPriorityTodos.push(todo.task);
        break;
      case "medium":
        mediumPriorityTodos.push(todo.task);
        break;
      case "low":
        lowPriorityTodos.push(todo.task);
        break;
    }
  }
}

console.log("\nPending Todos by Priority:");
if (highPriorityTodos.length > 0) {
  console.log("🔴 High Priority:", highPriorityTodos.join(", "));
}
if (mediumPriorityTodos.length > 0) {
  console.log("🟡 Medium Priority:", mediumPriorityTodos.join(", "));
}
if (lowPriorityTodos.length > 0) {
  console.log("🟢 Low Priority:", lowPriorityTodos.join(", "));
}

// Calculate completion percentage
const completionPercentage = (completedCount / todos.length * 100).toFixed(1);
console.log(`\nCompletion Rate: ${completionPercentage}%`);

// Add new todo
const newTodo = {
  id: todos.length + 1,
  task: "Review code",
  completed: false,
  priority: "medium"
};

todos.push(newTodo);
console.log(`\nAdded new todo: "${newTodo.task}"`);
console.log(`Total todos: ${todos.length}`);