Question

这里的简洁并不明智，所以我做了一些改变，把一切都搞清楚了。我仍然在我的智慧＆＃39;最终试图解决这个问题并做出一些建议的改变。

我试图在驱动程序中调用该方法来添加在Student-class中定义的名为students的对象，以添加到Course-class中找到的名单中，以便驱动程序可以打印出谁在课程中。 Course-class有一个名为addStudent的方法，它返回一个布尔表达式。根据是否有足够的空间来添加学生，将添加学生。不允许使用ArrayList-class（即ArrayList - 无法使用某些东西）。

以下是我所拥有的：

以下是我的学生班：

public class Student {
private String name;
private String iD;
private boolean tuitionPaid;
/**Constructor*/
public Student(String studentName, String studentID)
{
    name = studentName;
    iD = studentID; 
}
/**Getters and Setters are below*/
public String getStudentName()
{
    return name;
}
public void setStudentName(String studentName)
{
    name = studentName;
}
public String getStudentID()
{
    return iD;
}
public void setStudentID(String studentID)
{
    name = studentID;
}
/**The toString method below*/
public String toString()
{
    String message = name + iD;
    return message;
}
}

以下是课程课程：

public class Course {
private String name;
private int maxSize;
private String[] roster;

public Course(String courseName, int courseMaxSize)
{
    name = courseName;
    maxSize = courseMaxSize;
}


/**Getters and Setters are below*/
public String getCourseName()
{
    return name;
}
public void setCourseName(String courseName)
{
    name = courseName;
}
public int getCourseMaxSize()
{
    return maxSize;
}
public void setCourseMaxSize(int courseMaxSize)
{
    maxSize = courseMaxSize;
}
public String[] getCourseRoster()
{
    return roster;
}
public void setCourseRoster(Student s)
{
    String[] courseRoster = {s.toString()};//intended to pass the student name and ID
        roster = courseRoster;             //to the instance data variable

}

/**The toString method is below*/
public String toString()
{
    String message = name + " course has a class size of " + maxSize;
    return message;
}


/**Three requested methods are below*/
public boolean addStudent(Student s)
{

    boolean atCapacity = false;
    if(roster.length>=5)
    {
        String courseRoster[] = {s.toString()};//intended to pass the formal parameter
        roster = courseRoster;                 //to store as an instance data
        atCapacity = false;

    }
    else
    {
        atCapacity = true;      
    }
    return atCapacity;
}
public boolean dropStudent(Student s)
{
    boolean dropStudent = true;
    for( int index=0; index<roster.length - 1; index++ )//Goes through the roster
    {                                                   
        if( roster[index] == s.getStudentID() )//If a student matches, they are
        {
            s.setStudentID(null);               //dropped a student from a course
            s.setStudentName(null);             //their existence should be null
            dropStudent = true;
        }
        else
        {
            dropStudent = false;
        }
    }   
    return dropStudent;
}
public void printRoster()
{

        if(roster.length == 0)//In case there is no one in the roster
        {
            System.out.println("There is no one in this roster.");//this message prints
        }
        else
        {
        System.out.println(roster);//Everyone in class will be printed
        }
}
}

以下是驱动程序：

public class Project2DriverProgram {

public static void main(String[] args) {

    Student[] students = new Student[5];//Creates an array of objects from the Student-class
    students[0] = new Student("Bill", "123");//Instantiates the array at 0 with actual parameters

    Course newCourse = new Course("Philosophy", 5);//Creates an object and instantiates


    newCourse.getCourseRoster();
    newCourse.setCourseRoster(students[0]); //Sets the student to be in the roster

    newCourse.addStudent(students[0]);//Adds student to the course 


    newCourse.printRoster();//prints values of the roster

}

}

毕竟，我得到一个哈希码或一个内存地址。我希望这是可扩展的，这样当学生[1]成为现存时，那么也很容易被添加到课程名单中等等。

（P.S第一篇文章。这里不放弃。:)）

Answer 1

您的代码中存在逻辑错误：

if(roster.length>=5){
atCapacity = true; 
String[][] roster = {{s.getStudentName()}, {s.getStudentID()}};
}
else{
    atCapacity = false;
}//end of else statement

应改为：

if(!(roster.length>=5)){
 String[][] roster = {{s.getStudentName()}, {s.getStudentID()}};
 atCapacity = false;
}
else{
  atCapacity = true;
}

你反过来了，你当前的代码读取＆＃34;如果容量大于或等于5，那么添加一个新条目＆＃34;当你想要说＆＃34;如果容量不大于或等于5，添加一个新条目。＆＃34;

Answer 2

鉴于我的问题信息有限，我认为roster是Course的成员，其类型为Student[]，其中包含所有关注该课程的学生。我不知道你为什么在addStudent方法中有另一个局部二维String数组。

我建议将roster的类型更改为List<Student>（否则您需要单独保留计数，因为数组的长度是固定的）并保持课程的容量类成员名为capacity。如果调用成功而不是相反，我还建议返回true方法addStudent。

addStudent的可能实现方式是：

public boolean addStudent(Student s) {
    if (this.roster.size() < this.capacity) { 
        this.roster.add(s);
        return true;
    }
    return false;
}

如何将学生添加到名单（来自Java中的不同类）？

2 个答案: