User input int to Array then use bubble sort to sort numbers

Question

This is my first time posting to this blog. I'm new to Java and I have an issue with using bubble sort when a user inputs a set of values. Below is my code; however, I'm looking more for advice then an answer because I won't learn the language with the answer.

Thanks for your help and again sorry if my code is a little convoluted. BTW, I just started to learn Java so I won't be able to follow very complex coding advice.

import java.util.Arrays;
public class bubbleSort{

    public static void main(String[] arg){

        java.util.Scanner input = new java.util.Scanner(System.in);
        System.out.println("Enter total amount of numbers:" );

        int n = input.nextInt();

        int [] numbers = new int[n];

        System.out.println("Enter the numbers: ");
        for (int i = 0; i < n; i++) {
           numbers[i] = input.nextInt();
        }

        System.out.println(list(n));

        bubbleSort(n);

        System.out.println(list(n));    
    }


    public static void bubbleSort(int[] n){

        boolean flag;

        do{

            flag = false; 

            for(int i = 0; i < n.length - 1; i++){

                if (n[i] > n[i + 1]){

                    int temp = n[i];
                    n[i] = n[i + 1];
                    n[i + 1] = temp;

                    flag = true;
                }

            }

        } while (flag);
    }
 }

Answer 1

Your code got a bit confused when you started referring to an undefined identifier list .

I think you need:

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

bubbleSort(numbers);

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

instead of:

System.out.println(list(n));

bubbleSort(n);

System.out.println(list(n));    

n is the number of input numbers, not something you would want to sort. numbers contains the input data, and is a much more reasonable thing to sort.

Answer 2

There are problems with your code.

System.out.println(list(n));//list(n)came out of nowhere

And you code seem to only sort out one of the array elements.

You can try this:

public class BubbleSort {
public static void main(String[] args){
    int[] myArray = new int[10];
    for(int i = 0; i < myArray.length; i++){
        myArray[i] = (int)(Math.random()* 100 + 1);
        System.out.print(myArray[i] + " ");
    }
    System.out.println();
    bubbleSort(myArray);
}
public static void bubbleSort(int[] array){
    for(int i = 0; i < array.length - 1; i++){
        for(int j = 0; j < array.length -1 - i; j++){
            if(array[j] > array[j+1]){
                int temp = array[j+1];
                array[j+1] = array[j];
                array[j] = temp;
            }
        }
    }
    for(int i = 0; i < array.length; i++){
        System.out.print(array[i] + " ");
    }
}

Answer 3

So lets put some more info about your code.

• First: Use the Java Naming Convention . Your class has the name bubbleSort when it should be BubbleSort
• Second: Don't create a method with the same name of the class unless it is aconstructor .
• Third: Java is Strongly typed which means (on your case) that if you create a method that receives a parameter as int[] n ( bubbleSort(int[] n) ) it means you only pass to it an array of int´s
• Fourth: Don't use methods that does not exists ( eg: list(n) , at least on your class )

These are good advices for the code you provided. Hope it helps you understand a bit more on the Java world.