notepad.py

import tkinter as tk
from tkinter import filedialog

class Notepad:
    def __init__(self, master):
        self.master = master
        self.master.title("Notepad Clone")

        self.text = tk.Text(self.master, undo=True)
        self.text.pack(fill=tk.BOTH, expand=1)

        self.menu = tk.Menu(self.master)
        self.master.config(menu=self.menu)

        file_menu = tk.Menu(self.menu)
        self.menu.add_cascade(label="File", menu=file_menu)
        file_menu.add_command(label="New", command=self.new_file)
        file_menu.add_command(label="Open", command=self.open_file)
        file_menu.add_command(label="Save", command=self.save_file)
        file_menu.add_separator()
        file_menu.add_command(label="Exit", command=self.master.quit)

    def new_file(self):
        self.text.delete("1.0", tk.END)

    def open_file(self):
        file_path = filedialog.askopenfilename()
        if file_path:
            with open(file_path, "r") as file:
                self.text.delete("1.0", tk.END)
                self.text.insert("1.0", file.read())

    def save_file(self):
        file_path = filedialog.asksaveasfilename(defaultextension=".txt")
        if file_path:
            with open(file_path, "w") as file:
                file.write(self.text.get("1.0", tk.END))

root = tk.Tk()
notepad = Notepad(root)
root.mainloop()