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

/*arraylist 存储数据是有序的 可重复的，
适合查询 遍历
*
*
**/
public class arrayListDemo {
    public static void main(String[] args) {
        ArrayList list=new ArrayList();
        //添加元素
        list.add("张三");
        list.add("李四");
        list.add("王五");
//        遍历元素
        for (Object name : list) {
            System.out.println(name);
        }
        System.out.println("*********************");
        //修改元素
        list.set(0, "刘三");
        Iterator it=list.iterator();
        while (it.hasNext())
        {
            System.out.println(it.next());
        }
        System.out.println("********************");
        //删除元素
       boolean in= list.remove("刘三");
        System.out.println(in);
        for (int i = 0; i < list.size(); i++) {
            System.out.println(list.get(i));
        }
        //查询王五的下标
         int a= list.indexOf("王五");
        System.out.println(a);
        //清空list
        int b=list.indexOf("张三");
        System.out.println(b);
        boolean bool=list.contains("李四");
        System.out.println("查询是否有李四这个人："+bool);
        boolean bool1=list.isEmpty();
        System.out.println("判断list集合是否为空"+bool1);
        System.out.println(list.indexOf(0));
        list.clear();

    }
}