Thread: Loop Error

Hi, I am beginner to Java. I wanted to create a method that will reverse elements of my array, but I keep getting error and I am not sure why.

I use Jeliot to see what are the problems, but everything there is fine except the return statement in my code. Could anyone help me to fix it?
public class ReverseMe {

public static String revio(String[] a){
        int N = a.length;
        String[] reverse = new String[N];
        for (int i = 0; i < N ; i++) {
            reverse[i] = a[N-i-1];
 
        }
        return reverse[N];
 
 
 
}
    public static void main (String[] args)
    {
        String[] myArray = {"1", "2", "3"};
        String arr = revio(myArray);
        System.out.println(arr);
   }
 }

Have you been here? I found it by googling "reverse array java"
Collections (Java Platform SE 7 )

Well I've been there, but I can't find anything there that might help me.
I know that I get this error because my array starts from 0 and the last index is 2. My program tried to access to index 3 which is not in range of 0 to 2. I can't eliminate it :/

java.lang.ArrayIndexOutOfBoundsException: 3
	at ReverseMes.reverseConcat(ReverseMes.java:10)
	at ReverseMes.main(ReverseMes.java:20)
	at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
	at sun.reflect.NativeMethodAccessorImpl.invoke(Unknown Source)
	at sun.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source)
	at java.lang.reflect.Method.invoke(Unknown Source)
	at edu.rice.cs.drjava.model.compiler.JavacCompiler.runCommand(JavacCompiler.java:272)
>

I already tried changing from return[N] to return[N-1] it's not the case, because I get only one value in my outcome : "1". I know that I can change from String revio(String[] a) to String[]revio(String[] a), but I would rather solve it my way.

Edit: Sorry, that was not correct.

I know that I can change from String revio(String[] a) to String[]revio(String[] a), but I would rather solve it my way.

I dont understand what you mean with that? What is "your way" of solving it, and what is the problem with returning a string array?

I went through it with Jeliot and I know that my problem is that it tries to get access to index 3 which is not in range of 0 to 2.. I know that my problem is the "return" statement which I can't fix.

public static String revio(String[] a){
  int N = a.length;
  StringBuilder reverse = new StringBuilder();
  for (int i = 0; i < N ; i++) {
  reverse.append(a[N-i-1]);  
  }
  return reverse.toString(); 
  }
 
 
public static void main (String[] args)
{
  String[] myArray = {"1", "2", "3"};  
  String arr = revio(myArray);
  System.out.println(arr);
}
}

This is my current and fully working code.

You're right. That's why I am curious how to solve it without StringBuilder. Any advice?

Start with your original code and the error in Post #9, fix that error which will lead to other syntax errors or coding mistakes, fix those, and you'll end up with code that works. That single error begins a chain of errors that collectively are preventing the code from doing what you'd like.

Originally Posted by yellowglow

You're right. That's why I am curious how to solve it without StringBuilder. Any advice?

try to swap your elements to reverse array

if u r returning a array then its return type should be an array...use public static string[] reverse(parameters)