ios - Reverse NSString recursively in category -

this question has answer here:

• reverse nsstring text 19 answers

i made category reversing nsstring in recursive way. i'm getting correct answer. i'm not sure if okay memory management. don't know memory management in objective-c.

any other efficient way highly admirable.

-(nsstring *)reversestring{     if ([self length]<2) {         return self;     } else {         return [[[self substringfromindex:1] reversestring] stringbyappendingstring:[self substringtoindex:1]];     } } 

however, question similar reverse nsstring text not duplicate because here i'm implementing recursion. , asked memory consumption not code example.

using recursion reverse string interesting thought exercise, goning slow , dreadful wasteful of memory. need create 2n temporary strings. (where n number of characters in string) n of strings 1 character long, , other n strings 1, 2, 3, 4, 5, etc. characters, n-1.

(memory allocation slow.)

plus create n stack frames. rmaddy says in comment, you'll cause stack overflow long strings.

if doing learn recursion, fine. otherwise, toss approach , write code loops through array backwards, appending each character mutable string.