Question

Write a recursive function that computes the reverse of a string

Answer 1

OO I like this one!!!

Answer 2

here's what I tried so far (Python):

newS=''
def reverse(s):
if s=='':
return newS
else:
newS=newS+s[-1]
return reverse(s[:-1])

doesn't work, but maybe you can tweak it?

Answer 3

try with s[::-1]

Answer 4

Also what language?

Answer 5

I would assume you would do a character read and just call the function until it's in and out of an array. so you would do a for loop from 0 to string.length and then do it backwards.

Answer 6

mine doesn't work because newS is not defined in the function environment, so the recursive call registers that value as undefined the second time trough the loop.

Answer 7

here is my latest try:

def rev(s):
if len(s)!=0:
newS=''
newS=newS+s[-1]
s=s[:-1]
#print statement to illustrate what is happening to s and newS
print newS, s
return rev(s)

I know what my problem is I just can't fix it. I don't know how or where to initiate the value newS. Where I have it it resets it to the empty string on every iteration. Still thinking how to fix that.

Answer 8

@Daniel_Añez your method, though it works, is not using iteration

Answer 9

@TuringTest I meant, within your function. Anyway, this works if you introduce the string like an object with quotation marks:

def reverse(s):
result =s[::-1]
return result

I couldn't figure out how to convert the input into a valid string within the function, str() doesn't work

Answer 10

#!/usr/bin/python

def reverse( string ):
if( len( string ) == 0 ):
return string

char = string[ 0 ]
return( reverse( string[ 1: ] ) + char )

if( __name__ == "__main__" ):
print reverse( "Hello World" )