13 阶乘之和

 1

 1 def f(x):
 2       if x == 0:
 3            return 0
 4       elif x == 1:
 5            return 1
 6       else:
 7             return (x * f(x - 1))
 8 
 9 while 1:
10         info = int(input(\'>>>:\'))
11         print(f(info))
12         info = input(\'还想试试吗？(输入n退出)\')
13         if info == \'n\':
14             break