代碼沒問題啊,為什么我運(yùn)行的時(shí)候出錯(cuò)了
import java.util.ArrayList;
import java.util.Arrays;
import java.util.List;
import java.util.Scanner;
public class SetTest {
public List<Course> coursesToSelect;
public SetTest(){
coursesToSelect=new ArrayList<Course>();
}
public void testAdd(){
Course cr1=new Course("1","數(shù)據(jù)結(jié)構(gòu)");
coursesToSelect.add(cr1);
Course temp=(Course) coursesToSelect.get(0);
// System.out.println("添加了課程:"+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("添加了課程:"+temp2.id+":"+temp2.name);
// coursesToSelect.add(cr1);
// Course temp0=(Course) coursesToSelect.get(2);
// System.out.println("添加了課程:"+temp.id+":"+temp.name);
Course[] course={new Course("3","離散數(shù)學(xué)"),new Course("4","匯編語言")};
coursesToSelect.addAll(Arrays.asList(course));
Course temp3=(Course) coursesToSelect.get(3);
Course temp4=(Course) coursesToSelect.get(4);
// 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(shù)學(xué)"),new Course("6","大學(xué)英語")};
coursesToSelect.addAll(2, Arrays.asList(course2));
Course temp5=(Course) coursesToSelect.get(2);
Course temp6=(Course) coursesToSelect.get(3);
// System.out.println("添加了兩門課程:"+temp5.id+":"+
// temp5.name+";"+temp6.id+":"+temp6.name);
}
public void testForEach(){
System.out.println("有如下課程待選(通過for each訪問):");
for(Object obj:coursesToSelect){
Course cr=(Course) obj;
System.out.println("課程:"+cr.id+":"+cr.name);
}
}
/**
* @param args
*/
public static void main(String[] args) {
// TODO Auto-generated method stub
SetTest st=new SetTest();
st.testAdd();
st.testForEach();
//創(chuàng)建一個(gè)學(xué)生對象
Student student=new Student("1","小明");
System.out.println("歡迎學(xué)生:"+student.name+"選課!");
//創(chuàng)建一個(gè)Scanner對象,用來接收從鍵盤輸入的課程ID
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){
if(cr.id.equals(courseid)){
student.courses.add(cr);
}
}
}
// //打印輸出學(xué)生所選的課程
// for (Course cr : student.courses) {
// System.out.println("選擇了課程:"+cr.id+":"+cr.name);
// }
st.testForEachForSet(student);
}
public void testForEachForSet(Student student){
for (Course cr : student.courses) {
System.out.println("選擇了課程:"+cr.id+":"+cr.name);
}
}
?
2022-04-29
Course temp3=(Course) coursesToSelect.get(3);
Course temp4=(Course) coursesToSelect.get(4);
把這兩處的get(3)和(4)改成(2)和(3)。原因是去掉了重復(fù)插入的課程(1,數(shù)據(jù)結(jié)構(gòu)),所以你的數(shù)組索引相應(yīng)都要減一
2019-08-22
你敢不敢貼 圖片 順便把報(bào)什么錯(cuò)的圖片貼出來? ?看的眼珠子疼還茶葉看不出來 這樣復(fù)制代碼格式看著太難了
2019-06-26
我的解決了?。?!?還是自己看代碼解決的好
2019-06-26
Exception in thread "main" java.lang.IndexOutOfBoundsException: Index 4 out of bounds for length 4
報(bào)出的結(jié)果是數(shù)組索引越界異常
真心不好好講課
2019-06-02
就前面的插入,你獲取課程的時(shí)候還是用的get,list是有序的,set是無序的