def to_roman(value):
    convert_result = ""
    digit_base = 1
    while value > 0:
        remainder = value % (digit_base * 10)
        convert_result = convert_one_digit_to_roman(remainder, digit_base) + convert_result
        digit_base *= 10
        value -= remainder
    return convert_result

def convert_one_digit_to_roman(raw_value, digit_base):
    candidates = "IVXLCDM"
    index = 0
    temp = digit_base
    while temp > 1:
        temp /= 10
        index += 2
    value = raw_value // digit_base
    if value <= 3:
        return candidates[index] * value
    if value == 4:
        return candidates[index] + candidates[index + 1]
    if value <= 8:
        return candidates[index + 1] + candidates[index] * (value - 5)
    if value == 9:
        return candidates[index] + candidates[index + 2]
    raise ValueError("無(wú)效輸入: " + str(raw_value))

from tkinter import *
from tkinter import ttk

def convert():
    try:
        value = num.get()
        if (value <= 0) or (value > 3999):
            result.set("無(wú)效輸入")
            return
        result.set(to_roman(value))
    except ValueError:
        pass

def to_roman(value):
    convert_result = ""
    digit_base = 1
    while value > 0:
        remainder = value % (digit_base * 10)
        convert_result = convert_one_digit_to_roman(remainder, digit_base) + convert_result
        digit_base *= 10
        value -= remainder
    return convert_result

def convert_one_digit_to_roman(raw_value, digit_base):
    candidates = "IVXLCDM"
    index = 0
    temp = digit_base
    while temp > 1:
        temp /= 10
        index += 2
    value = raw_value // digit_base
    if value <= 3:
        return candidates[index] * value
    if value == 4:
        return candidates[index] + candidates[index + 1]
    if value <= 8:
        return candidates[index + 1] + candidates[index] * (value - 5)
    if value == 9:
        return candidates[index] + candidates[index + 2]
    raise ValueError("無(wú)效輸入: " + str(raw_value))


root = Tk()
root.title("整數(shù)轉(zhuǎn)羅馬數(shù)字小工具")

mainframe = ttk.Frame(root, padding=(3, 3, 12, 12))
mainframe.grid(column=0, row=0, sticky=(N, W, E, S))

num = IntVar()
num_entry = ttk.Entry(mainframe, width=4, textvariable=num)
num_entry.grid(column=2, row=1, sticky=(W, E))

ttk.Button(mainframe, text="轉(zhuǎn)化為羅馬數(shù)字", command=convert).grid(column=1, row=2, sticky=W)

ttk.Label(mainframe, text="請(qǐng)輸入一個(gè)正整數(shù) (不要超過(guò)3999)").grid(column=1, row=1, sticky=W)

result = StringVar()
ttk.Label(mainframe, textvariable=result).grid(column=2, row=2, sticky=W)

root.columnconfigure(0, weight=1)
root.rowconfigure(0, weight=1)
mainframe.columnconfigure(2, weight=1)
for child in mainframe.winfo_children(): 
    child.grid_configure(padx=5, pady=5)

num_entry.focus()
root.bind("<Return>", convert)

root.mainloop()

python3 to_roman.py