CODEWITHSUNDEEP
javaruntime-errorindexoutofboundsexception
Lennygames
Lennygames

Reputation: 41

My java program is giving me an IndexOutOfBoundsException

When my program enters this section of my code it crashes and produces this error

public static boolean Search(ArrayList<String> ArrayToSearch,String word)
{
    String temp;
    boolean found = false;
    for(int counter = 0;found || counter < ArrayToSearch.size();counter++)
        {
        temp = ArrayToSearch.get(counter);
        if(temp.equals(word.toLowerCase()))
        {
            found = true;
            position = counter;
        }
    }
    return found;
}

ArrayToSearch are different array lists containing a single word per line which represents a dictionary. Word is the word the user wants searched for. This is the error it produces. Add is a method which calls this method and receives back a boolean from it

D:\>java Evan
Exception in thread "main" java.lang.IndexOutOfBoundsException: Index: 109680, Size: 109680
        at java.util.ArrayList.rangeCheck(Unknown Source)
        at java.util.ArrayList.get(Unknown Source)
        at Evan.Search(Evan.java:95)
        at Evan.Add(Evan.java:68)
        at Evan.main(Evan.java:53)

D:\>

Upvotes: 0

Views: 121

Answers (5)

nikis
nikis

Reputation: 11254

Take a look on the stop-condition found || counter < ArrayToSearch.size(). What if you've found the needed element? In such a case found will be true and stop-condition will always be true, your loop will never stop. The correct loop is the following:

public static boolean Search(ArrayList<String> ArrayToSearch,String word)
{
    String temp;
    for(int counter = 0;counter < ArrayToSearch.size();counter++)
    {
        temp = ArrayToSearch.get(counter);
        if(temp.equals(word.toLowerCase()))
        {
            position = counter;
            return true;
        }
    }
    return false;
}

Upvotes: 1

Mikhail
Mikhail

Reputation: 2935

wrong circle for() for(int counter = 0;found || counter < ArrayToSearch.size();counter++)

the problem is when found is false and count>ArrayToSearch.size() u will have IndexOutOfBoundsException

Upvotes: 0

Markus
Markus

Reputation: 1777

The problem is your for-loop. If the word is found you need to break out of the loop

public static boolean Search(ArrayList<String> ArrayToSearch,String word) {
    String temp;
    boolean found = false;
    for(int counter = 0; counter < ArrayToSearch.size(); counter++) {
      temp = ArrayToSearch.get(counter);
      if(temp.equals(word.toLowerCase())){
        position = counter;
        break; //found
      }
    }
    return found;
  }

Upvotes: 0

Benjamin
Benjamin

Reputation: 2296

Your Code :

          for(int counter = 0;found || counter < ArrayToSearch.size();counter++)

Write like :

         for(int counter = 0;counter < ArrayToSearch.size();counter++)

Upvotes: 0

Jon Skeet
Jon Skeet

Reputation: 1503819

This is the problem:

found || counter < ArrayToSearch.size()

If found ever becomes true, that will continue forever - or rather, until it goes bang because of this exception. I suspect you meant

!found && counter < ArrayToSearch.size()

In other words: "keep going while we haven't found the word and there's still more of the collection to look through."

However, it would be much clearer just to return directly as soon as you find the result. It would also be simpler if you used an enhanced for loop:

// Names change to follow conventions
public static boolean search(List<String> list, String word) {
    // TODO: Handle the possibility of anything being null
    for (String candidate : list) {
        if (candidate.equals(word)) {
            return true;
        }
    }
    return false;
}

Or even more simply, just use List.contains which does this already.

Upvotes: 5

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