How can I sort to associated arrays by using the elements of one of them only?

Question

The task was to create a program which organises a users name with their corresponding mark and displays this in descending order. I'm asking how to sort both arrays at the same time but only by comparing the elements of one of the arrays. As a restriction, I cannot use classes, only associated arrays.

int [] ArrMarks = new int [5];
String [] ArrNames = new String [5];

Button to Accept user input

for (int i = 0; i < 5; i++)
{
    ArrNames[i] = JOptionPane.showInputDialog("Enter a Name:");
    ArrMarks[i] = Integer.parseInt(JOptionPane.showInputDialog("Enter a mark:")); 
}

Display button including the part which sorts the code, this is the main part I am unsure of.

int Hi = ArrMarks[0];
for(int i = 0; i < 5; i++) {
    if(ArrMarks[i] > Hi) {
        Hi = ArrMarks[i];
    }
}

txaDisplay.append("Names:"+"\t\t"+"Marks");
for (int i = 0; i < 5; i++) {
    txaDisplay.append(ArrNames[i]+"\t\t"+ArrMarks[i]+"\n");
}

@Trobbins When I run the program it does not sort the array, I'm asking for a slight modification to my code that will enable this. — rubin.kazan, Apr 29 '15 at 14:28
Combine the name and the grades into one class, and then you can use: http://docs.oracle.com/javase/7/docs/api/java/util/Arrays.html#sort(T[],%20java.util.Comparator) — ControlAltDel, Apr 29 '15 at 14:29

score 2 · Answer 1 · edited Apr 29 '15 at 15:22

First of all, I would like to give a suggestion. Use lists instead of arrays. This kind of coding is not a good conventional way of coding. I will show a conventional way to handle the issue. You may take this if you like.

Create another class Mark.java with the following content

class Mark {
    Integer mark;
    String name;

    public Integer getMark() {
        return this.mark
    }
    public void setMark(Integer mark) {
        this.mark = mark
    }
    public String getName() {
        return this.name
    }
    public void setName(String name) {
        this.name = name
    }
}

Then in your current class create a List of this class.

List<Mark> marks = new ArrayList<Mark>();

Then after reading content from the user, you can add them to the list like following

for (int i = 0; i < 5; i++)
{
    Mark mark = new Mark();
    String name = JOptionPane.showInputDialog("Name:");
    Integer mark = Integer.parseInt(JOptionPane.showInputDialog("Mark:")); 
    marks.add(mark)
}

Write a comparator class named MarkComparator.java. It deals with the sorting part.

public class MarkComparator implements Comparator<Mark> {
    @Override
    public int compare(Mark m1, Mark m2) {
        return m1.getMark().compareTo(m2.getMark());
    }
}

The use

Collections.sort(marks, new MarkComparator());

Now the List<Mark> of marks will be sorted.

You may then view the list the same way.

txaDisplay.append("Names:"+"\t\t"+"Marks");
for (Mark mark : marks)
{
    txaDisplay.append(mark.getName()+"\t\t"+mark.getMark()+"\n");
}

Interesting idea, but OP cannot use classes =\ – Luiggi Mendoza Apr 29 '15 at 17:04 — Luiggi Mendoza, Apr 29 '15 at 17:04

rubin.kazan · Accepted Answer · 2015-04-29T17:33:13.757

The solution to my question required using a sorting technique to sort the names and marks, so that the program prints the corresponding mark to the name.

for(int i = 0; i < 5-1; i ++)
{
    for(int j = i +1; j < 5; j++)
{
 if (ArrMarks[i] < ArrMarks[j]) 

 {
    //sorting the names
    String temp = ArrNames[i];
    ArrNames[i] = ArrNames[j];
    ArrNames[j] = temp;

    //sorting the marks
    int temp1 = ArrMarks[i];
    ArrMarks[i] = ArrMarks[j];
    ArrMarks[j] = temp1;  

}  

}   
txaDisplay.append("Names:"+"\t\t"+"Marks"+"\n");

        txaDisplay.append(ArrNames[i]+"\t\t"+ArrMarks[i]+"\n"); 
}

How can I sort to associated arrays by using the elements of one of them only?

2 Answers2