import java.util.ArrayList;
import java.util.Arrays;
import java.util.Iterator;

public class ArraylistExamples {
    public static void  main(String args[]){
        ArrayList<String> list = new ArrayList<String>();
        //增加元素到list
        list.add("item1");
        list.add("item2");
        list.add(2,"item3");
        list.add("item4");
        //顯示list內容
        System.out.println("The arraylist contains the following elements: "+list);
        //檢查元素位置
        int pos = list.indexOf("item2");
        System.out.println("The  index of item2 is: "+pos);
        //檢查list是否為空
        boolean check = list.isEmpty();
        System.out.println("Checking if the arraylist is empty: "+check);
        //檢查list是否包含某元素
        boolean element = list.contains("item2");
        System.out.println("Checking if the arraylist contains item2: "+element);
        //遍歷list中元素
        //第一種方法：
        System.out.println("Retrieving items with loop using index and size list");
        for (int i = 0;i<list.size();i++) {
            System.out.println("index " + i + ":" + list.get(i));
        }
        //第二種方法：使用foreach迴圈
        System.out.println("Retrieving items using foreach loop");
        for (String str : list){
            System.out.println("item is: "+str);
        }
        //第三種：使用迭代器
        //hasNext()返回true表示連結串列中還有元素
        //next()返回下一個元素
        System.out.println("Retrieving items using iterator");
        for (Iterator<String> it = list.iterator();it.hasNext();){
            System.out.println("item is: "+it.next());
        }
        //替換元素
        list.set(1,"newitem");
        System.out.println("The arraylist after the replacement is: " + list);
        list.remove("item3");//移除第一次找到的“item3”
        list.remove(0);//移除元素
        System.out.println("The final contents of the arraylist are: " + list);
        //轉換Arraylist為Array
        String[] array = list.toArray(new String[list.size()]);
        System.out.println("The array is: "+ Arrays.toString(array));
    }
}