BubbleSort using integer Array

Question

I have been trying to implement Bubble Sort using simple integer array in java. However there seems to be some problem. Now i know that using ArrayList would be the best option and I would do that too. But why isnt it getting sorted with simple integer array.Here is the code

package sort;

public class BubbleSort {

    int array[]={1,5,3,32,54,6,87,5,1};
    int temp=0;
public void enter(){
    for(int i=0;i<array.length;i++){
        for(int j=0;j<(array.length-i);j++){
            if(array[j]>=array[j+1]){


                temp=array[j];
                array[j]=array[j+1];
                array[j+1]=temp;
                }

        }
    }
}
public void show(){

    for(int i:array){
    System.out.println(i);
    }
}
public static void main(String str[]){

    new BubbleSort().Enter();
    new BubbleSort().Show();
}
}

Its producing the same array as entered. Nothing is getting changed. The difference between a simple array and an ArrayList or Vector ,is just that they offer dynamic time expansion of array size.Is there anything more to it? I mean does simple array creates a different instance every time it is manipulated, just like Strings? It does seem to do so here.

Please note that it is convention in Java for package names to be lower-case, and method names to be camelCase. See docstore.mik.ua/orelly/java-ent/jnut/ch07_01.htm. It is surprisingly confusing when Java developers read code that violates this. — Duncan Jones
– Duncan Jones, Commented Sep 3, 2012 at 17:35
No this is not homework. And I am using eclipse This particular package has all the sorting programs. I dont know how to rename it.I know its not the right convention. I'll keep that in mind next time.Thank you that was so helpful — Kanwaljeet Singh
– Kanwaljeet Singh, Commented Sep 3, 2012 at 17:41

Jamie · Accepted Answer · 2012-09-03 17:40:12Z

5

The problem is that you're not assigning a name to the instantiation of your BubbleSort class.

new BubbleSort().Enter();
new BubbleSort().Show();

Your code creates a new BubbleSort class, and then sorts it. And then it creates another new (and completely separate) BubbleSort class, and displays that one instead - and it hasn't been sorted.

You want to give a name to your variable, so you can sort it and then display it, like this:

BubbleSort myBubbleSort = new BubbleSort();
myBubbleSort.Enter();
myBubbleSort.Show();

As a side note (and as pointed out in SiB's answer), you may also want to check out the Java Naming Conventions. Following these conventions makes your code more legible to other Java programmers, and includes things like using lowerCamelCase for method names, and UpperCamelCase for class names.

edited Sep 3, 2012 at 17:40

answered Sep 3, 2012 at 17:33

Jamie

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1 Comment

Kanwaljeet Singh Over a year ago

Thank you !! How did I miss that !

Bharat Sinha · Accepted Answer · 2012-09-03 17:32:31Z

5

Because you are sorting one instance and showing another.

new BubbleSort().Enter();
new BubbleSort().Show();

Use

BubbleSort bubbleSort = new BubbleSort();
bubbleSort.Enter();
bubbleSort.Show();

Also you should rename Enter() to enter() and Show() to show() to say the least.

answered Sep 3, 2012 at 17:32

Bharat Sinha

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Comments

Yamaneko · Accepted Answer · 2012-09-03 17:39:39Z

3

Because you are creating two different BubbleSort Objects, sorting the first one and displaying a different one.

It should have been....

public static void main(String str[]){

    BubbleSort sort = new BubbleSort();
    sort.Enter();
    sort.Show():

}

edited Sep 3, 2012 at 17:39

Yamaneko

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answered Sep 3, 2012 at 17:36

ibondre

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Comments

Eduardo Andrade · Accepted Answer · 2014-01-08 01:42:19Z

1

And the correct BubbleSort code is:

    int temp = 0;
    for (int i = 0; i < array.length; i++) {
        for (int j = 1; j < (array.length - i); j++) {
            if (array[j - 1] > array[j]) {
                temp = array[j - 1];
                array[j - 1] = array[j];
                array[j] = temp;
            }

        }
    }

I hope it helps someone else looking for it.

answered Jan 8, 2014 at 1:42

Eduardo Andrade

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