4-11程序出錯(cuò)
SetTest程序運(yùn)行老是出錯(cuò),可是命名沒有報(bào)錯(cuò)誤?、??
package com.imooc.collection;
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(yǔ)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:"+temp0.id+":"+temp0.name);
*/
/*
Course cr3=new Course("3","tesyt");
coursesToSelect.add(3, cr3);
*/
Course[] course={new Course("3","離散數(shù)學(xué)"),new Course("4","匯編語(yǔ)言")};
coursesToSelect.addAll(Arrays.asList(course));
Course temp3=(Course)coursesToSelect.get(3);
Course temp4=(Course)coursesToSelect.get(4);
//System.out.println("添加了課程:"+temp3.id+":"+temp3.name
// +"添加了課程:"+temp4.id+":"+temp4.name);
Course[] course2={new Course("5","高等數(shù)學(xué)"),new Course("6","大學(xué)英語(yǔ)")};
coursesToSelect.addAll(2, Arrays.asList(course2));
Course temp5=(Course)coursesToSelect.get(2);
Course temp6=(Course)coursesToSelect.get(3);
//System.out.println("添加了課程:"+temp5.id+":"+temp5.name
//+"添加了課程:"+temp6.id+":"+temp6.name);
}
public void testForEach()
{
System.out.println("有如下課程待選通過(guò)ForEach訪問(wèn):");
for(Object obj:coursesToSelect)
{
Course cr=(Course)obj;
System.out.println("課程:"+cr.id+":"+cr.name);
}
}
public static void main(String[] args) {
// TODO Auto-generated method stub
SetTest st=new SetTest();
st.testAdd();
st.testForEach();
Student student=new Student("1","小明");
System.out.println("歡迎學(xué)生"+student.name+"選課");
Scanner console=new Scanner(System.in);
for(int i=0;i<3;i++)
{
System.out.println("請(qǐng)輸入課程ID");
String courseId=console.next();
for(Course cr:st.coursesToSelect)
{
if(cr.id.equals(courseId))
{
student.courses.add(cr);
}
}
}
st.testForEachForSet(student);
}
public void testForEachForSet(Student student)
{
for (Course cr : student.courses)?
{
System.out.println("選擇課程"+cr.id+":"+cr.name);
}
}
}
2016-11-08
越界了 ?前面這個(gè)地方
Course[] course={new Course("3","離散數(shù)學(xué)"),new Course("4","匯編語(yǔ)言")};
coursesToSelect.addAll(Arrays.asList(course));
Course temp3=(Course)coursesToSelect.get(3);
Course temp4=(Course)coursesToSelect.get(4)
index 只有 0 1 2 3 ?你卻get(4),就應(yīng)該會(huì)運(yùn)行出錯(cuò)
2016-11-11
list不就是有序且可以重復(fù)嗎