Question

我有一个名为Student的构造函数：

public Student(String suppliedFirstName, String suppliedLastName, int suppliedAge) {
    firstName = suppliedFirstName;
    lastName = suppliedLastName;
age = suppliedAge;
        }

一个名为Section：

的构造函数

public Section(String inName, int inMaximum) {
    name = inName;
maximumStudents = inMaximum;

List<Student> studentRoster = new ArrayList<Student>();
List<Student> studentWaitList = new ArrayList<Student>();
}

我想通过调用学生构造函数将学生添加到studentRoster列表中的方法：

public void signUp(Student inStudent()) {
    if(studentRoster.size() == maximumStudents) {
studentWaitList.add(inStudent());
return;
}

studentRoster.add(inStudent());

}

在尝试执行此操作时，我仍然遇到错误，说我还没有完成MethodDeclaration。正确执行此操作的正确语法是什么？

Answer 1

试试这个：

public void signUp(Student inStudent) {
   if (studentRoster.size() == maximumStudents) {
       studentWaitList.add(inStudent);
       return;
   }
   studentRoster.add(inStudent);
}

Answer 2

如果您想将Student实例传递给signUp()方法，则应该是：

public void signUp(Student inStudent) {
    if(studentRoster.size() == maximumStudents) {
        studentWaitList.add(inStudent);
        return;
    }
    studentRoster.add(inStudent);
}

然后你必须调用如下方法：

signUp(new Student(...));

或

Student lastStudent = new Student(...);
signUp(lastStudent);

注意这样做，Student实例正在初始化，然后才传递给方法signUp。换句话说，构造函数在传递给方法之前就被调用了。

此外，您必须将studentRoster和studentWaitList声明为类Section的字段。在

public Section(String inName, int inMaximum) {
    name = inName;
    maximumStudents = inMaximum;
    List<Student> studentRoster = new ArrayList<Student>();
    List<Student> studentWaitList = new ArrayList<Student>();
}

它们被声明为局部变量。你可能想要这样做：

public class Section {
    List<Student> studentRoste;
    List<Student> studentWaitList;

    public Section(String inName, int inMaximum) {
        name = inName;
        maximumStudents = inMaximum;
        studentRoster = new ArrayList<Student>(); // INITIALIZE
        studentWaitList = new ArrayList<Student>();
    }
}

如何调用方法内的构造函数？

2 个答案: