Recursive method

[justride]

I have a method that recurivley removed leading character of a passed string that are unwanted. if a character at index 0 in the string is unwanted then I call the method again removing that index 0 untill a character that is wanted is found, then I want to return that string, however the string that is being returned is the very original string. I guess I am not understanding recursion properly?

 private String chop(String string){
     if ( !( doesCharacterExist(string.charAt(0)) ) ){
            string = string.substring(1,string.length());
            chop(string);
     }
     return string;
 }
If I do a print out on each iteration I see the string get smaller however the return is the original string, If I put an else{ return string } I get the same behavior to. I figured by renaming string I would eliminate the original string's memory, guess not.

Any suggestions?
THanks

 

[LFI]

The problem is that chop(...), upon returning, returns to the previous iteration of chop(...), and so on, until, finally, it is the originally-called instance of chop(...) that returns the original string (or, it looks like, maybe the one with the first character truncated.

change
chop(string);
to
string = chop(string);

That should do it.

Dave


~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
O Time, Strength, Cash, and Patience!

 

[justride]

sweet. thanks man

 

[Diancecht]

By the way, recursion is unneficient at runtime and difficult to read and maintain.

Cheers,
Dian