题目：输入某年某月某日，判断这一天是这一年的第几天？
程序分析：以3月5日为例，应该先把前两个月的加起来，然后再加上5天即本年的第几天，特殊情况，闰年且输入月份大于2时需考虑多加一天：
程序源代码：
实例
#!/usr/bin/python3year = int(input('year:\n'))month = int(input('month:\n'))day = int(input('day:\n'))months = (0,31,59,90,120,151,181,212,243,273,304,334)if0 < month <= 12: sum = months[month - 1]else: print('data error')sum += dayleap = 0if(year % 400 == 0)or((year % 4 == 0)and(year % 100 != 0)): leap = 1if(leap == 1)and(month > 2): sum += 1print('it is the %dth day.' % sum)
以上实例输出结果为：
year:
2015
month:
6
day:
7
it is the 158th day.
