Problem: Arrays and Sorting

[Rhez]

Code:

import java.io.*; //imports java input output
import java.awt.*; //imports java abstract window toolkit
import java.util.Random; //imports java Random from utilities

public class SortAssignment extends EasyApp
{
    public static void main(String[] args)
    {   new SortAssignment();   }
    
    int numArray[] = new int[20]; //new integer array with 20 blank elements
    
    
    Button bListNums = addButton("List Nums",30,50,100,30,this); //adds a new
                                                                 //button
    Button bBubbleSort = addButton("Bubble Sort",30,100,100,30,this);
    Button bSelectSort = addButton("Selection Sort",30,150,100,30,this);
    Button bRandomNums = addButton("Random Nums",30,200,100,30,this);
    List lNumList = addList("",150,30,200,350,this); //adds a new list or text
                                                     //area
    List lSortList = addList("",380,30,200,350,this);
    
    //constructor for objects of class SortAssignment
    //when button "List Nums" is pressed, method ListNums runs
    //when button "Bubble Sort" is pressed, method BubbleSort runs
    //when button "Selection Sort" is pressed, method SelectSort runs
    //when button "Random Nums" is press, method RandomNums runs
    public void actions(Object source,String command)
    {
        if(source == bListNums)
        {   ListNums(numArray); }
        else if(source == bBubbleSort)
        {   BubbleSort(numArray);   }
        else if(source == bSelectSort)
        {   SelectSort(numArray);   }
        else if(source == bRandomNums)
        {   RandomNums();   }
    }
    
    //First method
    public void ListNums(int numArray[])
    {
        lNumList.removeAll(); //clear NumList
        lSortList.removeAll(); //clear SortList
        for(int n = 0; n < 20; n++) //loops 20 times
        {
            numArray[n] = inputInt("Type in an integer."); //Asks user for an
                                                           //int value as n
                                                           //increases
            String theNum = Integer.toString(numArray[n]); //converts int
                                                           //to string
            lNumList.add(theNum); //list outputs what user inputted
        }
    }
    
    //BubbleSort method
    public void BubbleSort(int a[])
    {
        ...
    }
    
    //SelectionSort method
    public void SelectSort(int a[])
    {
        ...
    }
    
    public void RandomNums()
    {
        lNumList.removeAll();
        lSortList.removeAll();
        int z = inputInt("How many integers?"); //asks user for the number of
                                                //integers
        int numArray2[] = new int[z];
        for(int n = 0; n < z; n++) //loops z times
        {
            double x = Math.random(); //method random runs
            numArray2[n] = (int)Math.round(x*z);
            String theNum = Integer.toString(numArray2[n]); //converts int
                                                            //to string
            lNumList.add(theNum); //list outputs what the random integer was
        }
    }
}

Problem: So far there is no syntax error when compiled. What I want to do is create a method that asks the user how many integers will be in an array, and then the method will create this many random valued integers, store them in the array and output the random integers, the method made, on a list. When the user presses a sorting button (eg BubbleSort) that method should apply with the array given from RandomNums.
I know something like

...

public class SortAssignment extends EasyApp
{
    public static void main(String[] args)
    {   new SortAssignment();   }
    
    int numArray[] = new int[20]; //new integer array with 20 blank elements
    int numArray2[] = new int[z];

    ...

    public void actions(Object source,String command)
    {
        if(source == bListNums)
        {   ListNums(numArray); }
        else if(source == bBubbleSort)
        {   BubbleSort(numArray);   }
        else if(source == bSelectSort)
        {   SelectSort(numArray);   }
        else if(source == bRandomNums)
        {   RandomNums(numArray2);   }
    }

    ...

    public void RandomNums(int numArray2[])
    {
        lNumList.removeAll();
        lSortList.removeAll();
        int z = inputInt("How many integers?"); //asks user for the number of
                                                //integers
        for(int n = 0; n < z; n++) //loops z times
        {
            double x = Math.random(); //method random runs
            numArray2[n] = (int)Math.round(x*z);
            String theNum = Integer.toString(numArray2[n]); //converts int
                                                            //to string
            lNumList.add(theNum); //list outputs what the random integer was
        }
    }
}

won't work because z is not verified blah blah etc and if I made a null array I can't modify a final variable blah blah etc.
So what do I do?

[collin389]

Why dont you ask how many ints, then create an array, then return that array?

[Rhez]

...

public class SortAssignment extends EasyApp
{
    public static void main(String[] args)
    {   new SortAssignment();   }
    
    int numArray[] = new int[20]; //new integer array with 20 blank elements
    int numArray2[];

    ...    

    public void actions(Object source,String command)
    {
        if(source == bListNums)
        {   ListNums(numArray); }
        else if(source == bBubbleSort)
        {   BubbleSort(numArray);   }
        else if(source == bSelectSort)
        {   SelectSort(numArray);   }
        else if(source == bRandomNums)
        {   RandomNums();   }
    }
    
    ...

    public int[] RandomNums()
    {
        lNumList.removeAll();
        lSortList.removeAll();
        int z = inputInt("How many integers?"); //asks user for the number of
                                                //integers
        int numArray2[] = new int[z];
        for(int n = 0; n < z; n++) //loops z times
        {
            double x = Math.random(); //method random runs ranged 0<x<1
            numArray2[n] = (int)Math.round(x*z); //rounds x*z to the nearest
                                                 //whole number
            String theNum = Integer.toString(numArray2[n]); //converts int
                                                            //to string
            lNumList.add(theNum); //list outputs what the random integer was
        }
        return numArray2;
    }
}

Is this what you're telling me to do?

[collin389]

That could work if you set the object's array to the array getting returned, or if you wanted you could just set the object's array in RandomNums() like so:

...

public class SortAssignment extends EasyApp
{
    public static void main(String[] args)
    {   new SortAssignment();   }
    
    int numArray[] = new int[20]; //new integer array with 20 blank elements
    int numArray2[];

    ...    

    public void actions(Object source,String command)
    {
        if(source == bListNums)
        {   ListNums(numArray); }
        else if(source == bBubbleSort)
        {   BubbleSort(numArray);   }
        else if(source == bSelectSort)
        {   SelectSort(numArray);   }
        else if(source == bRandomNums)
        {   RandomNums();   }
    }
    
    ...

    public void RandomNums()
    {
        lNumList.removeAll();
        lSortList.removeAll();
        int z = inputInt("How many integers?"); //asks user for the number of
                                                //integers
        this.numArray2[] = new int[z];
        for(int n = 0; n < z; n++) //loops z times
        {
            double x = Math.random(); //method random runs ranged 0<x<1
            this.numArray2[n] = (int)Math.round(x*z); //rounds x*z to the nearest
                                                 //whole number
            String theNum = Integer.toString(this.numArray2[n]); //converts int
                                                            //to string
            lNumList.add(theNum); //list outputs what the random integer was
        }

    }
}

It's up to you how you want your code to work.

[Rhez]

I tried what you suggested, but

        this.numArray2[] = new int[z];

was highlighted as "illegal start of expression" when I was compiling

[collin389]

Sorry, it would be: this.numArray2 = new int[z];

[Rhez]

Ok, so I tried this (underlined were the changes):

public class SortAssignment extends EasyApp
{
    public static void main(String[] args)
    {   new SortAssignment();   }
    
    int numArray[] = new int[20]; //new integer array with 20 blank elements
    [U]//(deleted numArray2[])[/U]
    ...

    public void actions(Object source,String command)
    {
        if(source == bListNums)
        {   ListNums(numArray); }
        else if(source == bBubbleSort)
        {   BubbleSort(numArray);   }
        else if(source == bSelectSort)
        {   SelectSort(numArray);   }
        else if(source == bRandomNums)
        {   [U]RandomNums(numArray);[/U]   }
    }

    ...
    
    [U]public int[] RandomNums(int numArray[])[/U]
    {
        lNumList.removeAll();
        lSortList.removeAll();
        int z = inputInt("How many integers?"); //asks user for the number of
                                                //integers
        [U]this.numArray = new int[z];[/U]
        for(int n = 0; n < z; n++) //loops z times
        {
            double x = Math.random(); //method random runs ranged 0<x<1
            numArray[n] = (int)Math.round(x*z); //rounds x*z to the nearest
                                                 //whole number
            String theNum = Integer.toString(numArray[n]); //converts int
                                                           //to string
            lNumList.add(theNum); //list outputs what the random integer was
        }
        [U]return numArray;[/U]
    }
}

No syntax errors were found when compiled, but when running after I clicked "Random Nums", entered a number (let's say 5) and selected "Bubble/Selection Sort", the output was 5 zeros. The amount needed to be sorted was correct but now there seems to be something missing for the correct output. What is needed to be done?

[Rhez]

bump; sorry, but I still need help here.