英文:
Print an array in tester class
问题
我试图在Course类的测试类中返回学生数组，但是我一直收到一个“class expected”错误。我尝试过使用 students[].TestCourse，但那也不起作用。
public class Course {
private String courseName;
private String[] students = new String[4];
private int numberOfStudents;
public Course(String courseName) {
this.courseName = courseName;
}
public void addStudent(String student) {
if (numberOfStudents == students.length) {
String[] copy = new String[students.length * 2];
System.arraycopy(students, 0, copy, 0, students.length);
students = copy;
}
students[numberOfStudents] = student;
numberOfStudents++;
}
public String[] getStudents() {
return students;
}
public void dropStudent(String student) {
for (int i = 0; i < students.length; i++) {
if (students[i] == student) {
students[i] = null;
}
for (i = i; i < students.length - 1; i++) {
students[i] = students[i + 1];
}
}
}
}
public class TestCourse {
public static void main() {
Course compScience = new Course("Computer Science");
compScience.addStudent("Jack");
compScience.addStudent("Dean");
compScience.addStudent("Leon");
compScience.dropStudent("Dean");
System.out.println("The students currently in this course are " + students[]);
}
}
英文:
I am trying to return the array of students in a tester class for the Course class but I keep getting a .class expected error. I've tried to do
students[].TestCourse but that doesn't work either.
public class Course {
private String courseName;
private String[] students = new String[4];
private int numberOfStudents;
public Course(String courseName) {
this.courseName = courseName;
}
public void addStudent(String student) {
if (numberOfStudents == students.length) {
String [] copy = new String [students.length*2];
System.arraycopy(students,0,copy,0,students.length);
students = copy;
}
students[numberOfStudents] = student;
numberOfStudents++;
}
public String[] getStudents() {
return students;
}
public void dropStudent(String student) {
for (int i=0;i<students.length;i++) {
if (students[i]==student) {
students[i] = null;
}
for (i=i;i<students.length-1;i++) {
students[i] = students[i+1];
}
}
}
}
public class TestCourse {
public static void main() {
Course compScience = new Course("Computer Science");
compScience.addStudent("Jack");
compScience.addStudent("Dean");
compScience.addStudent("Leon");
compScience.dropStudent("Dean");
System.out.println("The students currently in this course are "+ students[]);
}
}
答案1
得分: 0
将您的main方法中的这行代码更改为：
System.out.println("目前在这门课程中的学生有：" + Arrays.toString(compScience.getStudents()));
然后它应该能够正常运行！
您所做的只是尝试直接调用类的字段，而您需要通过您创建的引用来访问它，即Course compScience = new Course("计算机科学")...然后调用它的方法getStudents()，如下所示compScience.getStudents()。要获取数组的内容，您需要将此方法调用包装在Arrays.toString()中，如上所示。
英文:
Change the line in your main method to:
System.out.println("The students currently in this course are "+ Arrays.toString(compScience.getStudents()));
and it should fire up!
All you've done is try to call the field of a class directly when you need to access it via the reference you created Course compScience = new Course("Computer Science"); ... then call it's method getStudents() as follows compScience.getStudents(). To get the contents of the array you then need to wrap this method call in Arrays.toString() as above.
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