Unit 7 Homework

• Hack 1 - Descending and Swap
• Hack 3 - Ascending, Descending, Neither

Hack 1 - Descending and Swap

Sort an ArrayList in descending order and swap the first and last elements.

import java.util.ArrayList;
import java.util.Collections;

ArrayList<String> songs = new ArrayList<>();
songs.add("Shake It Off");
songs.add("In Da Club");
songs.add("Party In The USA");
songs.add("I Ain't Worried");
songs.add("One Dance");
songs.add("I Wanna Benz");

public void print(ArrayList<String> songs){
    for (String str : songs){
        System.out.println(str);
    }
}

// shows descending order
System.out.println("------------------");
Collections.sort(songs, Collections.reverseOrder());
System.out.println("Song's Descending Order: ");
print(songs);

System.out.println();
System.out.println("------------------");
// swaps 1st and 6th list items
System.out.println("Swap 1st & Last Element: ");
String temp = songs.get(0);
songs.remove(0);
songs.add(0,songs.get(songs.size()-1));
songs.remove(songs.size()-1);
songs.add(songs.size(), temp);

print(songs);

------------------
Song's Descending Order: 
Shake It Off
Party In The USA
One Dance
In Da Club
I Wanna Benz
I Ain't Worried

------------------
Swap 1st & Last Element: 
I Ain't Worried
Party In The USA
One Dance
In Da Club
I Wanna Benz
Shake It Off

Hack 3 - Ascending, Descending, Neither

Return "ascending" if the list is sorted in ascending order, return "descending" if it is descending, and return "neither" if neither.

import java.util.ArrayList;

public class ArrayChecker {
    // Here is the code to check if array list is sorted in Ascending order or not
    boolean checkSorting(ArrayList< String > arraylist){
        boolean isSorted=true;
        for(int i=1;i < arraylist.size();i++){
            if(arraylist.get(i-1).compareTo(arraylist.get(i)) > 0){
                isSorted= false;
                break;
            }
        }
        return isSorted;
    }
    public static void main(String[] args) {
        ArrayList < String > al=new ArrayList < String >();
        al.add("1, 2, 3, 4, 5, 6");
        System.out.println(al);
        ArrayChecker alDemo=new ArrayChecker();
        System.out.println("Is List Ascending: "+alDemo.checkSorting(al));
        al.remove("1, 2, 3, 4, 5, 6");
        al.add("6, 5, 4, 3, 2, 1");
        System.out.println(al);
        ArrayChecker alDemo1=new ArrayChecker();
        System.out.println("Is List Descending: "+alDemo1.checkSorting(al));
        al.remove("6, 5, 4, 3, 2, 1");
    }
}
ArrayChecker.main(null);

[1, 2, 3, 4, 5, 6]
Is List Ascending: true
[6, 5, 4, 3, 2, 1]
Is List Descending: true