# -*- coding: utf-8 -*-

#python 27

#xiaodeng

#http://www.cnblogs.com/BeginMan/p/3223356.html

#递归2

'非递归方式'

sum=0

#没有sum=0，会出现如下错误提示

'''

Traceback (most recent call last):

  File "C:\Users\Administrator\Desktop\new.py", line 12, in <module>

    sum+=obj

TypeError: unsupported operand type(s) for +=: 'builtin_function_or_method' and 'int'

'''

for obj in range(5):

    sum+=obj

print sum        #

#递归方式

def foo(n):

    if n>0:

        return n+foo(n-1)

    if n<=0:

        return 0

print foo(4)