todo_file.py

import os #os.system() #cls

#global variable
todo = []


def addTasks():
    global todo
    while True:
        task  = input('task to add: ')
        if task == 'exit':
            print('bye')
            break
        todo.append(task)

def printTodo():
    num = 0
    for task in todo:
        print(f'{num} - {task}')
        num = num + 1
    input('...')

def printMenu():
    print('0-Exit')
    print('1-Add Todo')
    print('2-Print Todo')
    print('3-Update Todo')
    print('4-Delete Todo')
    print('5-Save To file')

def updateData():
    printTodo()
    ind = input('Enter index to Update: ')
    ind = int(ind)
    value = input('Enter the todo you want to update: ')
    todo[ind] = value
    print('task is updated')

def deleteData():
    global todo
    printTodo()
    ind = input('Enter index to Delete: ')
    ind = int(ind)
    del todo[ind]
    print('task is deleted')

def saveToFile():
    out_file = open('todo.txt','w')
    for t in todo:
        out_file.write(t+'\n')
    out_file.close()

def readFromFile():
    global todo
    in_file = open('todo.txt','r')
    data = in_file.readlines()
    in_file.close()
    for d in data:
        d = d.rstrip() #remove '\n'
        todo.append(d)

#Real program START HERE
if __name__ == '__main__': #တိုက်ရိုက်ခေါ်သုံးတာ ဖြစ်ခဲ့ရင် အလုပ်လုပ်မယ်
    readFromFile()
    while True:
        os.system('cls')
        printMenu()
        ans = input('Wht is your choice: 0,1,2,3,4,5: ')
        if ans == '0':
            print('bye')
            saveToFile()
            exit(0)
        elif ans == '1':
            addTasks()
        elif ans == '2':
            printTodo()
        elif ans == '3':
            updateData()
        elif ans == '4':
            deleteData()
        elif ans == '5':
            saveToFile()