集合练习题之二

package cn.itcast.demo1;

public class Student {
		private String name ;
		private double TotalScore;
		public String getName() {
			return name;
		}
		public void setName(String name) {
			this.name = name;
		}
		public Student(String name, double totalScore) {
			this.name = name;
			TotalScore = totalScore;
		}
		public double getTotalScore() {
			return TotalScore;
		}
		public Student() {
		}
		public void setTotalScore(double totalScore) {
			TotalScore = totalScore;
		}
		@Override
		public String toString() {
			return name + ", TotalScore=" + TotalScore;
		}
}
 
/*
 1.有5个学生，每个学生有三门功课
 2.从键盘输入以上数据(姓名，三门课成绩)
 3.输入格式为：zhangshan，30，40，60并计算出总成绩
 4.把学生信息和计算出来的总成绩按从低到高的顺序进行存储
  分析：
 （1）定义一个学生类，属性：姓名，总成绩
 （2）将学生对象存到ArrayList中
 （3）Collections工具类中有一个方法，public static <T> void sort(List<T> list,Comparator<? super T> c)
             只能传list的实现类
 */public class Test1 {
	public static void main(String[] args) {
		Scanner sc = new Scanner(System.in);
		List<Student> list = new ArrayList<Student>();
		for (int i = 0; i < 5; i++) {
			System.out.println("请输入学生姓名和成绩：");
			String str = sc.nextLine();
			String[] arr = str.split(",");
			double score = 0;
			for (int j = 1; j < arr.length; j++) {
				score += Double.parseDouble(arr[j]);
			}
			list.add(new Student(arr[0], score));
		}

		Collections.sort(list, new Comparator<Student>() {
			@Override
			public int compare(Student o1, Student o2) {
				//返回值>0,降序           <0,升序                  =0,原样排列
				return (int) (o1.getTotalScore() - o2.getTotalScore());
			}
		});
		
		//遍历集合
		for (Student student : list) { System.out.println(student); }
		
		//不用匿名内部类
		/*
		 *  MyComparator myCom = new MyComparator();
		 *  Collections.sort(list,myCom);
		 */

	}

}
//自定义一个比较器类，去实现Comparator
class MyComparator implements Comparator<Student> {
	@Override
	public int compare(Student o1, Student o2) {
		return (int) (o1.getTotalScore() - o2.getTotalScore());
	}
}