java12.06

import java.awt.List;
import java.util.ArrayList;
import java.util.Iterator;
public class Test {

	public static void main(String[] args) {
//		集合遍历元素，以List为例
		/*ArrayList<String> list = new ArrayList<String>();
		list.add("aaa");
		list.add("bbb");
		list.add("ccc");
		System.out.println("第一种方法：");
		for (int i = 0; i < list.size(); i++) {
			System.out.println(list.get(i));
		}
		System.out.println("第二种方法：");
		Iterator<String> iter = list.iterator();
		while(iter.hasNext()) {
			System.out.println(iter.next());
		}
		System.out.println("第三种方法：");
		for(String s:list) {
			System.out.println(s);
		}*/
		
		Student s1 = new Student("2023210001","张三",80);
		Student s2 = new Student("2023210002","李四",85);
		Student s3 = new Student("2023210003","王五",90);
		ArrayList<Student> studentList = new ArrayList<Student>();
		studentList.add(s1);
		studentList.add(s2);
		studentList.add(s3);
		System.out.println("集合全部信息");
		for(Student s:studentList) {
			System.out.println(s);
		}
		System.out.println("-----------------------");
		System.out.println("下标为1的学生信息为："+studentList.get(1));
		System.out.println("-----------------------");
		studentList.remove(1);
		System.out.println("删除李四之后的集合元素：");
		for(Student s:studentList) {
			System.out.println(s);
		}
		System.out.println("------------------------");
		System.out.println("修改王五的分数:");
		s3.setScore(99);
		System.out.println("修改王五分数后的集合：");
		for(Student s:studentList) {
			System.out.println(s);
		}
		
		
		
	}
	
	
}

class Student{
	 private String sno;
	 private String sname;
	 private int score;
	 public Student() {}
	 public Student(String sno,String sname,int score) {
		 this.sno = sno;
		 this.sname = sname;
		 this.score = score;
	 }
	public String getSno() {
		return sno;
	}
	public void setSno(String sno) {
		this.sno = sno;
	}
	public String getSname() {
		return sname;
	}
	public void setSname(String sname) {
		this.sname = sname;
	}
	public int getScore() {
		return score;
	}
	public void setScore(int score) {
		this.score = score;
	}
	public String toString() {//重写toString
		return "学号："+sno+",姓名："+sname+",分数："+score;
	}
	 
}

import java.awt.List;
import java.util.ArrayList;
import java.util.Iterator;
import java.util.LinkedList;
public class Test {

	public static void main(String[] args) {
		String a = "A",b = "b",c = "C",test = "Test";
		LinkedList<String>list = new LinkedList<String>();
		list.add(a);
		list.add(b);
		list.add(c);
		System.out.println("集合中的元素为：");
		for (int i = 0; i < list.size(); i++) {
			System.out.println("索引位置为"+i+"的元素为："+list.get(i));
		}
		System.out.println("获取并输出表头对象："+list.getFirst());
		System.out.println("----------------------------");
		list.addFirst(test);
		System.out.println("在表头添加新元素，添加之后的集合为:");
		for (int i = 0; i < list.size(); i++) {
			System.out.println(list.get(i));
		}
		System.out.println("使用add添加ddd，默认添加到末尾：");
		list.add("ddd");
		for (int i = 0; i < list.size(); i++) {
			System.out.println(list.get(i));
		}
		list.removeFirst();
		System.out.println("移除表头元素之后的集合：");
		for(String s:list) {
			System.out.println(s);
		}
		System.out.println("移除表头元素之后的表头元素为："+list.getFirst());
		
	}
	
	
}

import java.awt.List;
import java.util.ArrayList;
import java.util.HashSet;
import java.util.Iterator;
import java.util.LinkedHashSet;
import java.util.LinkedList;
import java.util.Set;
public class Test {
//hashSet遍历结果无序，linkedHashSet的遍历结果与输入顺序一致。
	public static void main(String[] args) {
		Set<String> hashSet = new HashSet<String>();
		Set<String> linkedHashSet = new LinkedHashSet<String>();
		hashSet.add("aaa");
		hashSet.add("bbb");
		hashSet.add("ccc");
		hashSet.add("aaa");
		linkedHashSet.add("aaa");
		linkedHashSet.add("bbb");
		linkedHashSet.add("ccc");
		linkedHashSet.add("aaa");
		System.out.println("HashSet遍历结果："+hashSet);
		System.out.println("linkedHashSet遍历结果："+linkedHashSet);
	}
}