TQC+ 程式語言 Python 3 _ 407 不定數迴圈-閏年判斷

說明：
(1) 請撰寫一程式，以不定數迴圈的方式讓使用者輸入西元年份，然後判斷它是否為閏年（leap year）或平年。其判斷規則如下：每四年一閏，每百年不閏，但每四百年也一閏。
(2) 假設此不定數迴圈輸入-9999則會結束此迴圈。

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輸入與輸出會交雜如下，輸出的部份以粗體字表示
2017
2017 is not a leap year.
2000
2000 is a leap year.
2016
2016 is a leap year.
2009
2009 is not a leap year.
2018
2018 is not a leap year.
-9999

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程式碼：

year = int(input())

while year != -9999:
    if year % 400 == 0:
        print(year, 'is a leap year.')
    elif year % 100 == 0:
        print(year, 'is not a leap year.')
    elif year % 4 == 0:
        print(year, 'is a leap year.')
    else:
        print(year, 'is not a leap year.')

    year = int(input())