Why won't my array print out correctly?

Question

I am trying to write a simple program using the code below to make a single dimensional array that you can then call a value from using the index numbers. I am using java and eclipse as my compiler. Whenever I try to debug or run the program, the full array prints out as this: [I@1fa8d3b.

class Array    
{
public static void main(String[] args)
{
    int[] MyArray = new int[] {15, 45, 34, 78, 65, 47, 90, 32, 54, 10};
    System.out.println("The full array is:");
    System.out.println(MyArray);
    System.out.println("The 4th entry in the data is: " + MyArray[3]);
}
}

The correct data entry prints out when it is called though. I have tried to look for answers online as to what I should do, but I could not find anything that actually works. I am just starting to learn Java so there could be a very simple answer to this that I am just overlooking. If anyone has any ideas, I would be greatly appreciative.

Arrays have the default implementation of `equals()`, `hashCode()`, and `toString()`. — Eng.Fouad, Apr 25 '13 at 14:30

Kyle · Answer 1 · 2013-04-25T14:46:17.843

Java is an object oriented language. When you are calling System.out.print(MyArray); in Java you are actually printing ~~the address of the object on the heap in memory~~ the toString code from it's parent class Object, the code is shown below contributed by the comment from EngFouad, sorry for misspeaking. The weird String you see printed out is the reference the computer uses to find your data when you ask for something associated with the variable MyArray.

As stated by the other answers, to print out the data of your object you can use the Array class's built in .toString() method. This will print the data from the object instead of just the object reference.

System.out.println(Arrays.toString(MyArray);

Correction Actually it is toString() of the class Object: getClass().getName() + "@" + Integer.toHexString(hashCode()). – Eng.Fouad

Mistake above was corrected thanks for the comments, hate to give the wrong information. I misunderstood it myself. Here is the API reference to see the code:

http://docs.oracle.com/javase/1.5.0/docs/api/java/lang/Object.html#toString()

Actually it is `toString()` of the class `Object`: `getClass().getName() + "@" + Integer.toHexString(hashCode())`. — Eng.Fouad, Apr 25 '13 at 14:37
@Eng.Fouad and MarkRotteveel thanks for the corrections, making an edit now. I misspoke, I thought it was the address from my education. — Kyle, Apr 25 '13 at 14:43

score 3 · Answer 2 · edited May 23 '17 at 12:10

3

Use:

System.out.println(Arrays.toString(MyArray));

In order to print the array elements. In your case you used the default Object.toString() implementation, which is not so informative...

edited May 23 '17 at 12:10

Community

1
1

answered Apr 25 '13 at 14:28

BobTheBuilder

18,858
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score 2 · Answer 3 · answered Apr 25 '13 at 14:28

2

Use this instead:

System.out.println(Arrays.toString(MyArray));

API Reference: Arrays.toString(int[])

answered Apr 25 '13 at 14:28

durron597

31,968
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It worked, thanks! I was correct in thinking that it was a very simple fix. – user2320169 Apr 25 '13 at 14:31
@user2320169 This is not a fix, it is a java language feature. Learn what the `Object` `toString()` method does. – Sotirios Delimanolis Apr 25 '13 at 14:33

score 0 · Answer 4 · answered Apr 25 '13 at 14:30

0

to print the array you need to use the loop. for example:

for (int i: MyArray){
System.out.print(i + " ")}

answered Apr 25 '13 at 14:30

Nikitin Mikhail

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Why won't my array print out correctly?

4 Answers4

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