main.py

import json
import os

FILE = "tasks.json"

def load_tasks():
    if os.path.exists(FILE):
        with open(FILE, "r") as f:
            return json.load(f)
    return []

def save_tasks(tasks):
    with open(FILE, "w") as f:
        json.dump(tasks, f)

def show_tasks(tasks):
    if not tasks:
        print("No tasks yet!")
    else:
        for i, t in enumerate(tasks, start=1):
            status = "✔" if t["done"] else "✗"
            print(f"{i}. {t['task']} [{status}]")

def main():
    tasks = load_tasks()
    while True:
        print("\n1. Add task\n2. View tasks\n3. Mark done\n4. Exit")
        choice = input("Choose: ")

        if choice == "1":
            task = input("Enter task: ")
            tasks.append({"task": task, "done": False})
            save_tasks(tasks)
        elif choice == "2":
            show_tasks(tasks)
        elif choice == "3":
            show_tasks(tasks)
            num = int(input("Task number to mark done: ")) - 1
            if 0 <= num < len(tasks):
                tasks[num]["done"] = True
                save_tasks(tasks)
        elif choice == "4":
            break
        else:
            print("Invalid choice!")

if __name__ == "__main__":
    main()