“請輸入學生已選的課程名稱：”之后打回車，再輸入“高等數學”。

輸入高等數學的時候打個回車就不會出現這狀況了

package?come.collection;

import?java.util.ArrayList;
import?java.util.Arrays;
import?java.util.List;
import?java.util.Scanner;

public?class?testSet?{
	
	public?List?<Course>?coursesToSelect;
	
	public?Scanner?console;
	public?Student?student;
	
	public?testSet(){
		coursesToSelect?=?new?ArrayList<Course>();
	}
	public?void?testAdd(){
		Course?cr1?=new?Course("1",?"數據結構");
		coursesToSelect.add(cr1);
		Course?temp?=?(Course)coursesToSelect.get(0);
		//System.out.println("備選課程"+temp.id+"?"+temp.name);
		
		
		Course?cr2?=?new?Course("2","c語言");
		coursesToSelect.add(0,?cr2);
		Course?temp2?=?(Course)coursesToSelect.get(0);
		//System.out.println("備選課程"+temp2.id+"?"+temp2.name);
		
		//Course?cr11?=new?Course("1",?"數據結構");
		//coursesToSelect.add(cr11);
		//Course?temp0?=?(Course)coursesToSelect.get(2);
		//System.out.println("備選課程"+temp0.id+"?"+temp0.name);
		
		
		
//		Course?cr3?=?new?Course("3","test");
//		coursesToSelect.add(4,?cr3);
		
		Course[]?course?=?{new?Course("3","計算機網絡"),new?Course("4","匯編語言")};
		coursesToSelect.addAll(Arrays.asList(course));
		Course?temp3?=?(Course)coursesToSelect.get(2);
		Course?temp4?=?(Course)coursesToSelect.get(3);
		//System.out.println("添加了兩門課程:"+temp3.id+"?"+temp3.name+";"+temp4.id+"?"+temp4.name);
				
		Course[]?course2?=?{new?Course("5","高等數學"),new?Course("6","線性代數")};
		coursesToSelect.addAll(2,?Arrays.asList(course2));
		Course?temp5?=?(Course)coursesToSelect.get(2);
		Course?temp6?=?(Course)coursesToSelect.get(3);
		//System.out.println("又添加了兩門課程:"+temp5.id+"?"+temp5.name+";"+temp6.id+"?"+temp6.name);
		
		}
	???public??void?testForEach(){
		System.out.println("有如下課程(3)：");
		for(Object?obj?:?coursesToSelect){
			Course?cr?=?(Course)?obj;
			System.out.println("課程："+cr.id+"?"+cr.name);
		}
			
	??}
		public?void?testForEachForSet(Student?student){
			System.out.println("共選擇了："+student.courses.size()+"門課程！");
			for(Course?cr?:?student.courses){
				System.out.println("選擇了課程："+cr.id+"?"+cr.name);
			}
		}
//創建學生對象并選課
		public?void?creatStudentAndSelectCourse(){
			?student?=new?Student("1","小明");
			System.out.println("歡迎學生"+student.name+"選課！");
	Scanner?console?=?new?Scanner(System.in);
	for(int?i=0;i<3;i++){
		System.out.println("請輸入課程ID：");
		String?courseID?=?console.next();
		for(Course?cr?:?coursesToSelect?){
??//Set中不能重復！????????
			if(cr.id.equals(courseID)){
????????????	student.courses.add(cr);
????????????student.courses.add(null);
//????????	student.courses.add(cr);
????????????	}
????????????
	}
}

		}?
		public?void?testSetContains(){
			System.out.println("請輸入已選課程名稱：");
			console=new?Scanner(System.in);
			String?name?=?console.next();
			?Course?course2?=?new?Course();
			?course2.name=name;
			?System.out.println("新創建的課程："+course2.name);
			?System.out.println("備選課程中是否包含課程："+course2.name+","+
					?student.courses.contains(course2));
		}
	public?static?void?main(String[]?args)?{
		//?TODO?Auto-generated?method?stub

		testSet?st?=?new?testSet();
		st.testAdd();
		st.testForEach();
		st.creatStudentAndSelectCourse();
		st.testSetContains();
		/**
//		?*?創建一個新的學生對象
//		?*/
//		Student?student?=new?Student("1","小明");
//				System.out.println("歡迎學生"+student.name+"選課！");
//		Scanner?console?=?new?Scanner(System.in);
//		for(int?i=0;i<3;i++){
//			System.out.println("請輸入課程ID：");
//			String?courseID?=?console.next();
//			for(Course?cr?:?st.coursesToSelect?){
//??????//Set中不能重復！????????
//				if(cr.id.equals(courseID)){
//????????????????	student.courses.add(cr);
//????????????????student.courses.add(null);
////????????????	student.courses.add(cr);
????????????????	}
????????????????
		
	

??//?st.testForEachForSet(student);
}

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