Free Coding Apps

```jsx import React, { useState } from 'react'; const styles = { container: { maxWidth: '600px', margin: '0 auto', padding: '20px', }, form: { display: 'flex', flexDirection: 'column', marginBottom: '20px', }, input: { margin: '5px 0', padding: '5px', }, button: { margin: '5px 0', padding: '5px 10px', backgroundColor: '#4CAF50', color: 'white', border: 'none', cursor: 'pointer', }, task: { display: 'flex', alignItems: 'center', marginBottom: '10px', }, completed: { textDecoration: 'line-through', color: 'red', }, }; function TodoList() { const [tasks, setTasks] = useState([]); const [newTask, setNewTask] = useState({ description: '', category: '' }); const [editingTask, setEditingTask] = useState(null); const handleInputChange = (e) => { setNewTask({ ...newTask, [e.target.name]: e.target.value }); }; const handleSubmit = (e) => { e.preventDefault(); if (editingTask) { setTasks(tasks.map(task => task.id === editingTask.id ? { ...task, ...newTask } : task)); setEditingTask(null); } else { setTasks([...tasks, { id: Date.now(), ...newTask, completed: false }]); } setNewTask({ description: '', category: '' }); }; const toggleComplete = (id) => { setTasks(tasks.map(task => task.id === id ? { ...task, completed: !task.completed } : task)); }; const deleteTask = (id) => { setTasks(tasks.filter(task => task.id !== id)); }; const editTask = (task) => { setEditingTask(task); setNewTask({ description: task.description, category: task.category }); }; return ( <div style={styles.container}> <h1>Todo List</h1> <form onSubmit={handleSubmit} style={styles.form}> <input type="text" name="description" value={newTask.description} onChange={handleInputChange} placeholder="Task description" style={styles.input} /> <input type="text" name="category" value={newTask.category} onChange={handleInputChange} placeholder="Category" style={styles.input} /> <button type="submit" style={styles.button}> {editingTask ? 'Update Task' : 'Add Task'} </button> </form> <div> {tasks.map(task => ( <div key={task.id} style={styles.task}> <input type="checkbox" checked={task.completed} onChange={() => toggleComplete(task.id)} /> <span style={task.completed ? styles.completed : null}> {task.description} ({task.category}) </span> <button onClick={() => editTask(task)} style={styles.button}>Edit</button> <button onClick={() => deleteTask(task.id)} style={styles.button}>Delete</button> </div> ))} </div> <p>Total Completed Tasks: {tasks.filter(task => task.completed).length}</p> </div> ); } export default TodoList; ``` This React component implements a Todo List with the following features: - Adding new tasks with description and category - Editing existing tasks - Marking tasks as complete/incomplete - Deleting tasks - Displaying completed tasks with strikethrough text in red - Showing the total number of completed tasks To use this component, you would typically render it in your main App component or another parent component. Make sure to have React installed in your project before using this code.

```json { "version": "1.0.0", "elements": [ { "id": "section-1", "elType": "section", "settings": { "section_type": "inner", "background_background": "classic", "background_color": "#4567b7", "padding": { "unit": "px", "top": 50, "right": 50, "bottom": 50, "left": 50, "isLinked": true }, "margin": { "unit": "px", "top": 0, "right": 0, "bottom": 0, "left": 0, "isLinked": true }, "width": "full", "custom_width": { "unit": "%", "size": 100 }, "content_width": "full", "theme_style": "", "gap": { "unit": "px", "size": 10 }, "column_gap": { "unit": "px", "size": 10 }, "isCoral": "", "border": { "size": { "unit": "px", "top": 0, "right": 0, "bottom": 0, "left": 0 }, "border_color": "#ffffff", "border_style": "solid" }, "responsive": { "tablet": { "padding": { "top": 30, "right": 30, "bottom": 30, "left": 30 } }, "mobile": { "padding": { "top": 20, "right": 20, "bottom": 20, "left": 20 } } } }, "elements": [ { "id": "column-1", "elType": "column", "settings": { "width": "50", "offset": "", "custom_offset": "", "toggle_indicator": "", "background_background": "classic", "background_color": "", "padding": { "unit": "px", "top": 20, "right": 20, "bottom": 20, "left": 20, "isLinked": true }, "margin": { "unit": "px", "top": 0, "right": 0, "bottom": 0, "left": 0, "isLinked": true }, "border": { "size": { "unit": "px", "top": 0, "right": 0, "bottom": 0, "left": 0 }, "border_color": "#ffffff", "border_style": "solid" }, "responsive": { "tablet": {}, "mobile": {} } }, "elements": [ { "id": "image-1", "elType": "image", "settings": { "image": { "url": "https://via.placeholder.com/200x150", "id": 123, "alt": "Broker Image", "source": "library" }, "link_to": "none", "link": { "url": "", "is_external": "", "nofollow": "" }, "width": { "unit": "%", "size": 100 }, "align": "center" } } ] }, { "id": "column-2", "elType": "column", "settings": { "width": "50", "offset": "", "custom_offset": "", "toggle_indicator": "", "background_background": "classic", "background_color": "", "padding": { "unit": "px", "top": 20, "right": 20, "bottom": 20, "left": 20, "isLinked": true }, "margin": { "unit": "px", "top": 0, "right": 0, "bottom": 0, "left": 0, "isLinked": true }, "border": { "size": { "unit": "px", "top": 0, "right": 0, "bottom": 0, "left": 0 }, "border_color": "#ffffff", "border_style": "solid" }, "responsive": { "tablet": {}, "mobile": {} } }, "elements": [ { "id": "text-1", "elType": "text-editor", "settings": { "editor": "<p>Welcome to Best Brokers Online, your premier destination for comparing top brokers and making informed investment decisions.</p>", "drop_cap": "", "text_color": "#ffffff", "font_size": { "unit": "px", "size": 18 }, "font_family": "Arial", "line_height": { "unit": "px", "size": 24 }, "text_align": "left" } } ] } ] }, { "id": "section-2", "elType": "section", "settings": { "section_type": "inner", "background_background": "classic", "background_color": "#6495ed", "padding": { "unit": "px", "top": 50, "right": 50, "bottom": 50, "left": 50, "isLinked": true }, "margin": { "unit": "px", "top": 0, "right": 0, "bottom": 0, "left": 0, "isLinked": true }, "width": "full", "custom_width": { "unit": "%", "size": 100 }, "content_width": "full", "theme_style": "", "gap": { "unit": "px", "size": 10 }, "column_gap": { "unit": "px", "size": 10 }, "isCoral": "", "border": { "size": { "unit": "px", "top": 0, "right": 0, "bottom": 0, "left": 0 }, "border_color": "#ffffff", "border_style": "solid" }, "responsive": { "tablet": { "padding": { "top": 30, "right": 30, "bottom": 30, "left": 30 } }, "mobile": { "padding": { "top": 20, "right": 20, "bottom": 20, "left": 20 } } } }, "elements": [ { "id": "column-3", "elType": "column", "settings": { "width": "100", "offset": "", "custom_offset": "", "toggle_indicator": "", "background_background": "classic", "background_color": "", "padding": { "unit": "px", "top": 20, "right": 20, "bottom": 20, "left": 20, "isLinked": true }, "margin": { "unit": "px", "top": 0, "right": 0, "bottom": 0, "left": 0, "isLinked": true }, "border": { "size": { "unit": "px", "top": 0, "right": 0, "bottom": 0, "left": 0 }, "border_color": "#ffffff", "border_style": "solid" }, "responsive": { "tablet": {}, "mobile": {} } }, "elements": [ { "id": "image-2", "elType": "image", "settings": { "image": { "url": "https://via.placeholder.com/400x200", "id": 456, "alt": "Investment Image", "source": "library" }, "link_to": "none", "link": { "url": "", "is_external": "", "nofollow": "" }, "width": { "unit": "%", "size": 100 }, "align": "center" } } ] } ] }, { "id": "section-3", "elType": "section", "settings": { "section_type": "inner", "background_background": "classic", "background_color": "#87ceeb", "padding": { "unit": "px", "top": 50, "right": 50, "bottom": 50, "left": 50, "isLinked": true }, "margin": { "unit": "px", "top": 0, "right": 0, "bottom": 0, "left": 0, "isLinked": true }, "width": "full", "custom_width": { "unit": "%", "size": 100 }, "content_width": "full", "theme_style": "", "gap": { "unit": "px", "size": 10 }, "column_gap": { "unit": "px", "size": 10 }, "isCoral": "", "border": { "size": { "unit": "px", "top": 0, "right": 0, "bottom": 0, "left": 0 }, "border_color": "#ffffff", "border_style": "solid" }, "responsive": { "tablet": { "padding": { "top": 30, "right": 30, "bottom": 30, "left": 30 } }, "mobile": { "padding": { "top": 20, "right": 20, "bottom": 20, "left": 20 } } } }, "elements": [ { "id": "column-4", "elType": "column", "settings": { "width": "100", "offset": "", "custom_offset": "", "toggle_indicator": "", "background_background": "classic", "background_color": "", "padding": { "unit": "px", "top": 20, "right": 20, "bottom": 20, "left": 20, "isLinked": true }, "margin": { "unit": "px", "top": 0, "right": 0, "bottom": 0, "left": 0, "isLinked": true }, "border": { "size": { "unit": "px", "top": 0, "right": 0, "bottom": 0, "left": 0 }, "border_color": "#ffffff", "border_style": "solid" }, "responsive": { "tablet": {}, "mobile": {} } }, "elements": [ { "id": "text-2", "elType": "text-editor", "settings": { "editor": "<p>At Best Brokers Online, we provide you with the tools and insights to navigate the complex world of investments with confidence.</p>", "drop_cap": "", "text_color": "#ffffff", "font_size": { "unit": "px", "size": 16 }, "font_family": "Arial", "line_height": { "unit": "px", "size": 22 }, "text_align": "left" } } ] } ] }, { "id": "section-4", "elType": "section", "settings": { "section_type": "footer", "background_background": "classic", "background_color": "#4567b7", "padding": { "unit": "px", "top": 20, "right": 20, "bottom": 20, "left": 20, "isLinked": true }, "margin": { "unit": "px", "top": 0, "right": 0, "bottom": 0, "left": 0, "isLinked": true }, "width": "full", "custom_width": { "unit": "%", "size": 100 }, "content_width": "full", "theme_style": "", "gap": { "unit": "px", "size": 10 }, "column_gap": { "unit": "px", "size": 10 }, "isCoral": "", "border": { "size": { "unit": "px", "top": 0, "right": 0, "bottom": 0, "left": 0 }, "border_color": "#ffffff", "border_style": "solid" }, "responsive": { "tablet": {}, "mobile": {} } }, "elements": [ { "id": "column-5", "elType": "column", "settings": { "width": "100", "offset": "", "custom_offset": "", "toggle_indicator": "", "background_background": "classic", "background_color": "", "padding": { "unit": "px", "top": 10, "right": 10, "bottom": 10, "left": 10, "isLinked": true }, "margin": { "unit": "px", "top": 0, "right": 0, "bottom": 0, "left": 0, "isLinked": true }, "border": { "size": { "unit": "px", "top": 0, "right": 0, "bottom": 0, "left": 0 }, "border_color": "#ffffff", "border_style": "solid" }, "responsive": { "tablet": {}, "mobile": {} } }, "elements": [ { "id": "text-3", "elType": "text-editor", "settings": { "editor": "<p>Best4D Investor, LLC<br>2023-001303230<br>5830 E2nd St Ste6300<br>Casper, WY82609<br>USA<br>+1 036 000 2589<br>[email protected]</p>", "drop_cap": "", "text_color": "#ffffff", "font_size": { "unit": "px", "size": 12 }, "font_family": "Arial", "line_height": { "unit": "px", "size": 16 }, "text_align": "left" } } ] } ] } ] } ```

**Hello World in Python** ``` print("Hello, World!") ``` This code will output `Hello, World!` when run. **Explanation:** * `print()` is a built-in function in Python that prints its argument to the console. * The string `"Hello, World!"` is the argument passed to `print()`, which is then printed to the console. Save this code in a file with a `.py` extension (e.g., `hello.py`) and run it using Python (e.g., `python hello.py`) to see the output.

## Creating a Harry Potter-based Game on Roblox with Wands and Spells To create a Harry Potter-based game on Roblox, you'll need to create a wand and implement spells that can be cast using the left mouse click. Here's a step-by-step guide to help you achieve this: ### Creating the Wand 1. Create a new `Part` in the `Workspace` and rename it to "Wand". This will serve as the player's wand. 2. Add a `.LocalScript` to the Wand and name it "WandScript". 3. In the WandScript, add the following code to initialize the wand: ```lua local player = game.Players.LocalPlayer local wand = script.Parent -- Set the wand's properties wand.Handle = wand:WaitForChild("Handle") -- Assuming the handle is a child of the wand wand.Tip = wand:WaitForChild("Tip") -- Assuming the tip is a child of the wand ``` ### Implementing Spells with Left Click To implement spells with left click, you'll need to detect when the player clicks the left mouse button and then cast the corresponding spell. 1. Add a `UserInputService` to the WandScript to detect mouse clicks: ```lua local userInputService = game:GetService("UserInputService") -- Function to cast a spell when the left mouse button is clicked local function castSpell() -- Get the spell from the player's inventory or a preset spell local spell = getSpellFromInventory() -- Implement this function to get the spell from the player's inventory -- Cast the spell (more on this later) castSpellEffect(spell) end -- Connect the left mouse button click event to the castSpell function userInputService.InputBegan:Connect(function(input) if input.UserInputType == Enum.UserInputType.MouseButton1 then castSpell() end end) ``` ### Casting Spells To cast a spell, you'll need to create a function that will handle the spell's effects. Here's a basic implementation: ```lua local function castSpellEffect(spell) -- Get the spell's properties (e.g., spell name, damage, range, etc.) local spellName = spell.Name local damage = spell.Damage local range = spell.Range -- Create a spell effect (e.g., a fireball, a blast of air, etc.) local spellEffect = Instance.new("Explosion") spellEffect.Position = wand.Tip.Position spellEffect.Parent = workspace -- Apply the spell's effects (e.g., damage to enemies, environment, etc.) -- Implement this logic based on the spell's properties -- For example: local enemies = getEnemiesInRadius(wand.Tip.Position, range) for _, enemy in ipairs(enemies) do enemy:TakeDamage(damage) end -- Remove the spell effect after a short duration wait(1) spellEffect:Destroy() end ``` ### Adding Spells to the Player's Inventory To allow players to switch spells, you'll need to implement a system to store and retrieve spells from their inventory. You can do this using a `Folder` in the player's `StarterPack` or `Backpack`. 1. Create a `Folder` in the player's `StarterPack` or `Backpack` and name it "Spells". 2. Create new `Folder`s within the Spells folder to represent individual spells (e.g., "Fireball", "HealingBlast", etc.). 3. Add the spell's properties (e.g., damage, range, etc.) to the spell's folder as `IntValue`s or `StringValue`s. 4. Modify the `getSpellFromInventory` function to retrieve the currently selected spell from the player's inventory. Here's a basic implementation: ```lua local function getSpellFromInventory() local spellsFolder = game.Players.LocalPlayer.StarterPack.Spells local selectedSpell = spellsFolder:FindFirstChild("SelectedSpell") if selectedSpell then return selectedSpell end end ``` This is a basic outline to get you started. You can expand on this by adding more features, such as spell cooldowns, spell levels, and more. Remember to adjust the code to fit your specific game requirements and implement the necessary logic for handling spell effects, enemy AI, and other game mechanics. Good luck with your Harry Potter-based game on Roblox!

```python import hashlib import json import time from typing import List, Dict import threading import socket import sqlite3 from cryptography.hazmat.primitives import hashes from cryptography.hazmat.primitives.asymmetric import padding, rsa class Block: def __init__(self, index, transactions, timestamp, previous_hash): self.index = index self.transactions = transactions self.timestamp = timestamp self.previous_hash = previous_hash self.nonce = 0 self.hash = self.calculate_hash() def calculate_hash(self): block_string = json.dumps(self.__dict__, sort_keys=True) return hashlib.sha256(block_string.encode()).hexdigest() class Blockchain: def __init__(self): self.chain = [self.create_genesis_block()] self.difficulty = 4 self.pending_transactions = [] self.mining_reward = 10 self.nodes = set() self.lock = threading.Lock() def create_genesis_block(self): return Block(0, [], int(time.time()), "0") def get_latest_block(self): return self.chain[-1] def mine_pending_transactions(self, miner_address): with self.lock: block = Block(len(self.chain), self.pending_transactions, int(time.time()), self.get_latest_block().hash) block.mine_block(self.difficulty) self.chain.append(block) self.pending_transactions = [ {"from": "network", "to": miner_address, "amount": self.mining_reward} ] def add_transaction(self, transaction): if not all(k in transaction for k in ("from", "to", "amount", "signature")): raise ValueError("Invalid transaction") public_key = rsa.PublicKey.load_pkcs1(transaction['from'].encode()) message = f"{transaction['from']}{transaction['to']}{transaction['amount']}".encode() try: public_key.verify( transaction['signature'], message, padding.PSS( mgf=padding.MGF1(hashes.SHA256()), salt_length=padding.PSS.MAX_LENGTH ), hashes.SHA256() ) except: raise ValueError("Invalid transaction signature") self.pending_transactions.append(transaction) def is_chain_valid(self): for i in range(1, len(self.chain)): current_block = self.chain[i] previous_block = self.chain[i-1] if current_block.hash != current_block.calculate_hash(): return False if current_block.previous_hash != previous_block.hash: return False return True def add_node(self, address): parsed_url = urlparse(address) self.nodes.add(parsed_url.netloc) def replace_chain(self): network = self.nodes longest_chain = None max_length = len(self.chain) for node in network: response = requests.get(f'http://{node}/chain') if response.status_code == 200: length = response.json()['length'] chain = response.json()['chain'] if length > max_length and self.is_chain_valid(chain): max_length = length longest_chain = chain if longest_chain: self.chain = longest_chain return True return False def save_blockchain(blockchain, filename): with open(filename, 'w') as f: json.dump([vars(block) for block in blockchain.chain], f) def load_blockchain(filename): with open(filename, 'r') as f: chain_data = json.load(f) blockchain = Blockchain() blockchain.chain = [Block(**block_data) for block_data in chain_data] return blockchain # Network functionality def start_node(blockchain, port): node = socket.socket(socket.AF_INET, socket.SOCK_STREAM) node.bind(('', port)) node.listen(5) print(f"Node listening on port {port}") while True: client, addr = node.accept() threading.Thread(target=handle_client, args=(client, blockchain)).start() def handle_client(client, blockchain): request = client.recv(1024).decode() if request == "GET_CHAIN": client.send(json.dumps([vars(block) for block in blockchain.chain]).encode()) client.close() # Database functionality def init_db(): conn = sqlite3.connect('blockchain.db') c = conn.cursor() c.execute('''CREATE TABLE IF NOT EXISTS blocks (index INTEGER PRIMARY KEY, transactions TEXT, timestamp INTEGER, previous_hash TEXT, nonce INTEGER, hash TEXT)''') conn.commit() conn.close() def save_block_to_db(block): conn = sqlite3.connect('blockchain.db') c = conn.cursor() c.execute("INSERT INTO blocks VALUES (?, ?, ?, ?, ?, ?)", (block.index, json.dumps(block.transactions), block.timestamp, block.previous_hash, block.nonce, block.hash)) conn.commit() conn.close() def load_blockchain_from_db(): conn = sqlite3.connect('blockchain.db') c = conn.cursor() c.execute("SELECT * FROM blocks ORDER BY index") blocks = c.fetchall() conn.close() blockchain = Blockchain() blockchain.chain = [Block(b[0], json.loads(b[1]), b[2], b[3]) for b in blocks] for block in blockchain.chain: block.nonce = block.nonce block.hash = block.hash return blockchain # Usage example blockchain = Blockchain() init_db() # Generate RSA key pair for signing transactions private_key = rsa.generate_private_key( public_exponent=65537, key_size=2048 ) public_key = private_key.public_key() # Example transaction transaction = { "from": public_key.public_bytes( encoding=serialization.Encoding.PEM, format=serialization.PublicFormat.PKCS1 ).decode(), "to": "recipient_address", "amount": 5 } # Sign the transaction signature = private_key.sign( f"{transaction['from']}{transaction['to']}{transaction['amount']}".encode(), padding.PSS( mgf=padding.MGF1(hashes.SHA256()), salt_length=padding.PSS.MAX_LENGTH ), hashes.SHA256() ) transaction['signature'] = signature blockchain.add_transaction(transaction) blockchain.mine_pending_transactions("miner_address") # Save the blockchain to file and database save_blockchain(blockchain, 'blockchain.json') for block in blockchain.chain: save_block_to_db(block) # Start the node threading.Thread(target=start_node, args=(blockchain, 5000)).start() # In a real-world scenario, you would implement more comprehensive error handling, # logging, and security measures. This example provides a basic framework that can # be extended and improved upon. ``` This implementation includes: 1. A basic blockchain structure with blocks and transactions 2. Proof-of-Work consensus mechanism 3. Transaction signing and verification using RSA 4. Network functionality for distributed nodes 5. Persistent storage using both file-based and SQLite database storage 6. A simple node server to handle basic network requests To make this production-ready, you would need to add more robust error handling, implement a more advanced consensus mechanism, add more comprehensive testing, and optimize for performance. Additionally, you'd want to implement a proper API, add more security features, and create a user interface for interacting with the blockchain.

### Overview of the AI-Powered Mock Interview Platform The platform utilizes artificial intelligence to simulate real interview experiences. It is designed to help users prepare for job interviews by providing a dynamic and adaptive questioning process. #### Key Features: * **Targeted Interview Preparation**: Users can select a target company and role, allowing the system to tailor the interview questions to the specific position. * **Adaptive Questioning**: The AI analyzes the user's spoken answers and selects follow-up questions based on their responses, mimicking the behavior of a skilled interviewer. * **Real-time Feedback**: Users receive immediate, actionable feedback on their communication skills, thought process, and presentation style. * **Data Protection**: The platform ensures strong privacy controls to safeguard user data. #### Business Model: * **B2B Partnerships**: The platform focuses on partnerships with universities and bootcamps to enhance placement success rates and build trust among users. * **User Base Growth**: As the platform grows its user base, the AI engine learns from a larger dataset of real answers, improving its adaptability and human-like interaction. #### Unique Selling Proposition (USP): * **Real-time Adaptive Feedback Loop**: The platform's ability to provide personalized, real-time feedback and adapt to the user's responses sets it apart from static question banks and larger, less adaptable platforms.