基于用户输入创建学生数组

Question

我试图创建一个基于用户输入的数学学生、科学学生和计算机学生的数组。

所以基本上用户应该选择他们想要添加的学生，然后输入学生详细信息。

下面我添加了我到目前为止的代码：

public class Lab4 {
    public static final int DEBUG = 0;
    /**
     * @param args the command line arguments
     */
    public static void main(String[] args) {
        Student s[] = new Student[10];
        s[0] = new MathStudent(4,5);
        s[1] = new MathStudent(5,7);
        s[2] = new MathStudent(2,8);
        s[3] = new MathStudent(3,6);
        s[4] = new ScienceStudent(8,9);
        s[5] = new ScienceStudent(3,6);
        s[6] = new ScienceStudent(4,9);
        s[7] = new ComputerStudent(6,12);
        s[8] = new ComputerStudent(11,14);
        s[9] = new ComputerStudent(13,17);
    }

}

public class Student {
    private String name;
    private int age;
    public String gender = "na";
    public static int instances = 0;

    // Getters
    public int getAge(){
        return this.age;
    }
    public  String getName(){
        return this.name;
    }

    // Setters
    public void setAge(int age){
        this.age = age;
    }
    public void setName(String name){
        if (Lab4.DEBUG > 3) System.out.println("In Student.setName. Name = "+ name);
        this.name = name;
    }

    /**
     * Default constructor. Populates name,age,gender,course and phone Number 
     * with defaults
     */
    public Student(){
        instances++;
        this.age = 18;
        this.name = "Not Set";
        this.gender = "Not Set";
    }

    /** 
     * Constructor with parameters 
     * @param age integer
     * @param name String with the name
    */
    public Student(int age, String name){
        this.age = age;
        this.name = name;
    }

    /** 
     * Gender constructor
     * @param gender 
     */
    public Student(String gender){
        this(); // Must be the first line!
        this.gender = gender;

    }

    /**
     * Destructor
     * @throws Throwable 
     */
    protected void finalize() throws Throwable{
        //do finalization here
        instances--;
        super.finalize(); //not necessary if extending Object.
    } 

    public String toString (){
        return "Name: " + this.name + " Age: " + this.age + " Gender: " 
               + this.gender;
    }

    public String getSubjects(){
      return this.getSubjects();
    }
}

public class MathStudent extends Student {
    private float algebraGrade;
    private float calculusGrade;

    public MathStudent(float algebraGrade, float calculusGrade) {
        this.algebraGrade = algebraGrade;
        this.calculusGrade = calculusGrade;
    }

    public MathStudent() {
        super();
        algebraGrade = 6;
        calculusGrade = 4;
    }

    // Getters
    public void setAlgebraGrade(float algebraGrade){
        this.algebraGrade = algebraGrade;
    }
    public void setCalculusGrade(float calculusGrade){
        this.calculusGrade = calculusGrade;
    }

    // Setters
    public float getAlgebraGrade() {
        return this.algebraGrade;
    }
    public float getCalculusGrade() {
        return this.calculusGrade;
    }

    /**
     * Display information about the subject
     * @return 
     */
    @Override
    public String getSubjects(){
        return("Algebra Grade: " + algebraGrade + " Calculus Grade: " 
                + calculusGrade);
    }
}

public class ScienceStudent extends Student {
    private float physicsGrade;
    private float astronomyGrade;

    /**
     * Default constructor
     */
    public ScienceStudent() {
        super();
        physicsGrade = 6;
        astronomyGrade = 7;
    }

    public ScienceStudent(float physicsGrade, float astronomyGrade) {
        this.physicsGrade = physicsGrade;
        this.astronomyGrade = astronomyGrade;
    }

    // Getters
    public void setPhysicsGrade(float physicsGrade){
        this.physicsGrade = physicsGrade;
    }
    public void setAstronomyGrade(float astronomyGrade){
        this.astronomyGrade = astronomyGrade;
    }

    // Setters
    public float getPhysicsGrade() {
        return this.physicsGrade;
    }
    public float getAstronomyGrade() {
        return this.astronomyGrade;
    }

    /**
     * Display information about the subject
     * @return 
     */
     @Override
    public String getSubjects(){
        return("Physics Grade: " + physicsGrade + " Astronomy Grade: " 
                + astronomyGrade);
    } 
}

计算机学生班：

public class ComputerStudent extends Student {
    private float fortanGrade;
    private float adaGrade;

    /**
     * Default constructor
     */
    public ComputerStudent() {
        super();
        fortanGrade = 4;
        adaGrade = 9;
    }

    public ComputerStudent(float fortanGrade, float adaGrade) {
        this.fortanGrade = fortanGrade;
        this.adaGrade = adaGrade;
    }

    // Getters
    public void setFortanGrade(float fortanGrade){
        this.fortanGrade = fortanGrade;
    }
    public void setAdaGrade(float adaGrade){
        this.adaGrade = adaGrade;
    }

    // Setters
    public float getFortanGrade() {
        return this.fortanGrade;
    }
    public float getAdaGrade() {
        return this.adaGrade;
    }

    /**
     * Display information about the subject
     * @return 
     */
    @Override
    public String getSubjects(){
        return("Fortan Grade: " + fortanGrade + " Ada Grade: " + adaGrade); 
    }
}

我该怎么做？

Answer 1

您可以在每个输入上询问具有type的学生数，并动态创建对象。这里有一个例子

System.out.println("Enter total number of students");
int n = scannerObject.nextInt();
Student students[] = new Students[n];
for(int i=0;i<n;i++){
  int type = scannerObject.nextInt();
  if(type == 1)
   students[i] = new MathStudent();
}

同样，你也可以为别人写作。