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3时需考虑多加一天：

程序源代码：

#!/usr/bin/python
# -*- coding: UTF-8 -*-

year = int(raw_input('year:\n'))
month = int(raw_input('month:\n'))
day = int(raw_input('day:\n'))

months = (0,31,59,90,120,151,181,212,243,273,304,334)
if 0 < month <= 12:
    sum = months[month - 1]
else:
    print 'data error'
sum += day
leap = 0
if (year % 400 == 0) or ((year % 4 == 0) and (year % 100 != 0)):
    leap = 1
if (leap == 1) and (month > 2):
    sum += 1
print '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.