collection集合练习……

/
学生选课系统，用来练习collection集合。
/
import java.util.HashSet;
import java.util.Iterator;
import java.util.Set;

public class Student { //创建学生类
private int id ; //学生学号
private String name ; //学生姓名
private Set<Course> courses ; //学生所选课程

public Student(int id ,String name ){
    this.id = id ;
    this.name = name ;
    this.courses = new HashSet<Course>() ;
}
public void testAdd(Course course){        //添加课程。
    courses.add(course) ;
}
public void testRemove(Course course){ //删除所选课程
    courses.remove(course) ;
}
public void testIterator(){    //查看所选课程
    Iterator course = courses.iterator() ;
    while(course.hasNext()){
        System.out.println(course.next().toString());
    }
}
public Set<Course> getCourses(){
    return this.courses ;
}
public String toString(){
    return "学号："+this.id+"/t"+"姓名："+this.name;
}

}
public class Course { //创建课程类
private int id ; //课程编号
private String name ; //课程名称

public Course(){

}
public Course(int id , String name ){
    this.id = id ;
    this.name = name ;
}
public int getId(){
    return this.id ;
}
public String toString(){
    return "编号："+this.id+"\t"+"名称："+this.name ;
}

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

public class CoursesList { //学生选课清单
private ArrayList<Course> courses ; //备选课程

public CoursesList(){
    this.courses = new ArrayList<Course>() ;
}
public void testAdd(){
    Course course = new Course(1,"数据库基础") ;
    courses.add(course) ;

    Course course1 = new Course(2,"Java基础") ;
    courses.add(course1) ;

    Course [] course2 = new Course[]{new Course(3,"数据结构"),new Course(4,"算法基础")} ;
    courses.addAll(0,Arrays.asList(course2)) ;

    Course [] course3 = {new Course(5,"Oracle基础"),new Course(2,"Java基础")} ;
    courses.addAll(3, Arrays.asList(course3)) ;
}
public void testIterator(){
    System.out.println("有如下课程待选：");
    Iterator<Course> iterator = courses.iterator() ;
    while(iterator.hasNext()){
        System.out.println(iterator.next().toString());
    }
}
/*
public void testForeach(){
    System.out.println("有如下课程待选：");
    for(Course course : courses){
        System.out.println(course.toString());
    }
}
public void testFor(){
    System.out.println("有如下课程待选：");
    for(int i = 0 ; i < courses.size(); i++){
        System.out.println(courses.get(i).toString());
    }
}
*/
public void testRemove(){
    courses.remove(5) ;
}
public void testModify(){
    courses.set(3,new Course(5,"离散数学")) ;
}
public ArrayList<Course> getCourses(){
    return this.courses ;
}

}import java.util.Scanner;

public class TestArrayList {
public static void main(String [] args ){
CoursesList newcourse = new CoursesList() ;
newcourse.testAdd();
newcourse.testIterator();
// System.out.println("*");
// newcourse.testForeach() ;
// System.out.println("***");
// newcourse.testFor();
newcourse.testModify();
newcourse.testIterator();
newcourse.testRemove();
newcourse.testIterator();
Student student = new Student(1,"Jack") ;
System.out.println("每个人选修三门课程，请输入课程编号：");
Scanner input = new Scanner(System.in) ;
for(int i = 0 ; i < 3 ; i++ ){
System.out.println("请输入第"+(i+1)+"门课程编号：");
int num = input.nextInt();

        for(Course course : newcourse.getCourses()){
            if(course.getId() == num ){
                student.testAdd(course);
            }
        }
    }
    int n = 0 ;
    Label:do{
    System.out.println("你所选的课程清单如下：");
    student.testIterator();
    System.out.println("是否确定所选的课程?");
    System.out.println("请输入 Yes/No");
    String str = input.next();
    if(str.equals("Yes")){
        System.out.println("恭喜你选课成功！");
        break Label ;
    }else if(str.equals("No")){
        System.out.println("请输入你需要修改的编号：");
    }else{
        System.out.println("你输入有误，请重新输入：");
    }

    int j = input.nextInt() ;
    for(Course course : student.getCourses()){
        if(course.getId() == j){
            student.testRemove(course);
        }
    }
    System.out.println("已删除成功，请输入你要添加的课程的编号。");
    int m = input.nextInt() ;
    for(Course course : newcourse.getCourses()){
        if(course.getId() == m){
            student.testAdd(course);
        }
    }
    }while(n < 3 ) ;
} 

}