I'm new to arrayList and now I am having trouble with the output. It requires me to take the second char in String Owner compared to other and sort by descending. I tried by using a variable temp1 to swap 2 of them.

The list before run : (A8,1) (B1,2) (C7,3) (D2,4) (E6,5) (F3,6)

but my output is: (A8,1) (B1,2) (D2,4) (F3,6) (E6,5) (C7,3) (not correct)

@Override
public void f3(List<Cala> list) {
    for (int i = 0; i < list.size(); i  ) {
        char max = list.get(i).getOwner().charAt(1);
        for (int j = 1; j < list.size(); j  ) {
            char temp = list.get(j).getOwner().charAt(1);
            if (max < temp) {
                Cala temp1 = list.get(i);
                list.set(i, list.get(j));
                list.set(j, temp1);
            }
        }
    }
}

Please help me what is wrong with this :< Thank you guys

This is my class Cala. I cannot access to Main class because Main's file extension is Main.class

public class Cala {
    private String owner;
    private int price;

    public Cala(){
        owner = "";
        price = 0;
    }

    public Cala(String owner, int price) {
        this.owner = owner;
        this.price = price;
    }

    public String getOwner() {
        return owner;
    }

    public int getPrice() {
        return price;
    }

    public void setOwner(String owner) {
        this.owner = owner;
    }

    public void setPrice(int price) {
        this.price = price;
    }

    @Override
    public String toString() {
        return  "("  owner   ","   price  ")" ;
    }
}

CodePudding user response：

I understand that you want to sort the list of Cala objects, by the digit in the owner, using bubble sort algorithm. The following code does that:

import java.util.ArrayList;
import java.util.List;

public class Cala {
    private String owner;
    private int price;

    public Cala() {
        this("", 0);
    }

    public Cala(String owner, int price) {
        this.owner = owner;
        this.price = price;
    }

    public String getOwner() {
        return owner;
    }

    public int getPrice() {
        return price;
    }

    public void setOwner(String owner) {
        this.owner = owner;
    }

    public void setPrice(int price) {
        this.price = price;
    }

    @Override
    public String toString() {
        return "("   owner   ","   price   ")";
    }

    private static int getDigit(Cala cala) {
        if (cala != null) {
            String owner = cala.getOwner();
            if (owner.length() > 1) {
                char digit = owner.charAt(1);
                return digit - '0';
            }
            else {
                return 0;
            }
        }
        else {
            return 0;
        }
    }

    public static void main(String[] args) {
        List<Cala> list = new ArrayList<>();
        list.add(new Cala("A8",1));
        list.add(new Cala("B1",2));
        list.add(new Cala("C7",3));
        list.add(new Cala("D2",4));
        list.add(new Cala("E6",5));
        list.add(new Cala("F3",6));
        System.out.println("Before: "   list);
        int len = list.size();
        for (int i = 0; i < len - 1; i  ) {
            for (int j = 0; j < len - i - 1; j  ) {
                if (getDigit(list.get(j   1)) < getDigit(list.get(j))) {
                    Cala swap = list.get(j);
                    list.set(j, list.get(j   1));
                    list.set(j 1, swap);
                }
            }
        }
        System.out.println(" After: "   list);
    }
}

Running the above code produces the following output:

Before: [(A8,1), (B1,2), (C7,3), (D2,4), (E6,5), (F3,6)]
 After: [(B1,2), (D2,4), (F3,6), (E6,5), (C7,3), (A8,1)]

CodePudding user response：

I'm not sure about the variable names and everything, but this is what I came up with

for(int i = 0; i < arrayList.size(); i  ){
int temp = Integer.parseInt(arrayList.get(i).substring(1,2);
for(int j = 1; j < arrayList.size(); j  ){
int temp1 = Integer.parseInt(arrayList.get(j).substring(1,2);
if(j > i){
arrayList.swap(i, j);

The main thing I would try is potentially the parseInt, this code probably has a lot of problems but that's a baseline of what I would do