《Craking the Coding interview》python实现---02

###题目：翻转一个字符串
###思路：从字符串的最后一位开始，依次取
###实现：伪代码、函数、类实现

#伪代码：

#01
string=s
New_s=""
for i in range(1,len(string)+1):
New_s+=string[-i]

#02
string=s
New_s=""
def  reversal_str(n):
    New_s +=string[n]

return reversal_str(n-1)

###函数实现：

def rerversal_handler01(string):
	New_s=str()
	if string !=None:
		try:
			for i in range(1,len(string)+1):
				New_s+=string[-i]
		except TypeError as e:
			print(e)

		finally:
			print(New_s)

###类实现：

class ReversalStr:
         def __init__(self,string):
                  self.t=string
                  self.New_s=""

         def  reversal_str(self,n):
                  self.New_s +=self.t[n]
                  if n>=0:
                           return self.reversal_str(n-1)
                  else:
                           print(self.New_s)