How to use a StringBuffer?

So... I was trying to use this:


Is there any method available to insert a character at a specific position in a string?
For example:

st = "abde" <------ Original string
st= "abCde" <------ Add "C" in position 2

You can use StringBuffer to do this:

String st = new String("abcde");
st = StringBuffer(st).insert(2, "C").toString();


as an example for what I'm trying to do. Basically I just want to add a 1 or a 0 to the end of a pre-existing String. <-binary conversion stuff.
Anyway, so when i try to do it, Eclipse keeps telling me a I need to create a method for StringBuffer(String)..

example..
output = StringBuffer(output).insert("0").toString();

But it should be noted that I've already included: import java.lang.*;
in my code... Help?
Sorry if this seems dumb. I'm extremely new to java and coding in general.

The example I think forgot the word "new" in front of StringBuffer since you need to create a new StringBuffer object for this to work. Myself, I'd probably just use simple String concatenation unless you're doing this multiple times inside of a large or critical loop. If so, even then I'd not use a StringBuffer since it has extra unnecessary (in this case) overhead for thread-safety, and would use a StringBuilder object instead. You would use append(...) if adding to the end of the character sequence.

So for example

Code:

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output += "0";  // simple way

output = [color="red"][b]new[/b][/color] StringBuilder(output).append("0").toString(); // if in a critical loop or a possible bottleneck

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oh that was it. Thanks so much. =)

You're quite welcome.

Correction: if in a critical loop though, I'd create the StringBuilder object before the loop, append junk in inside the loop, and only call toString() on the StringBuilder after the loop.

Quote:

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Originally Posted by Hallowed

But it should be noted that I've already included: import java.lang.*;

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Hallowed,

You don't really need to import this package. This package comes inbuilt for every java code. :p

Goldest

Oh alright haha. I just read on a website to use it with that code. So I dunno =/