我在Java Assignment中需要一些帮助，这是一个用于管理phonecall的简单程序

Question

A1。创建一个名为PhoneCall的抽象类，其中包含电话号码的字符串字段和调用价格的双字段。

A2。此外，还包括一个构造函数，该构造函数需要一个电话号码参数并将价格设置为0.0。包括价格的设定方法。还包括三个摘要get方法 - 一个返回电话号码，另一个返回呼叫价格，第三个显示有关呼叫的信息。

A3。创建两个电话呼叫子类：IncomingPhoneCall和Outgoing Phone Call。

• IncomingPhoneCall构造函数将其电话号码参数传递给其父级构造函数，并将调用的价格设置为0.02。显示电话呼叫信息的方法显示电话号码，费率和呼叫价格（与费率相同）。

----- OutgoingPhoneCall类包含一个附加字段，用于在几分钟内保存呼叫时间。构造函数需要电话号码和时间。价格为每分钟0.04，显示方式显示通话详情，包括电话号码，每分钟费率，分钟数和总价。

---编写一个应用程序，演示您可以实例化并显示IncomingPhoneCall和OutgoingPhoneCall对象。将文件保存为PhoneCall.java，IncomingPhoneCall.java，OutgoingPhoneCall.java和DemoPhoneCalls.java。

我只做了以下事情：

public abstract class PhoneCall
{

    private String phoneno;
    private double price;

    public PhoneCall(String phoneno, double price)
    {
        this.phoneno =  phoneno;
        this.price = price;
    }
    public String getphoneno()
    {
        return phoneno;
    }
    public double getprice()
    {
        return price = 0.0;
    }

    public static void main(String[] args) {

    }

}
public class IncomingPhoneCall extends PhoneCall
{

    public IncomingPhoneCall(String phoneno, double price) {
        super(phoneno, price);

    }

}
public class OutgoingPhoneCall extends PhoneCall
{

    public OutgoingPhoneCall(String phoneno, double price) {
        super(phoneno, price);

    }

}

Answer 1

abstract class PhoneCall
{

    String phoneNumber;
    double price;

     PhoneCall(String phoneNumber)
    {
        this.phoneNumber =  phoneNumber;
        this.price = 0.0;
    }
    public String getPhoneNumber() {
        return phoneNumber;
    }

    public double getPrice() {
        return price;
    }

    public abstract void setPrice();

}
class IncomingPhoneCall extends PhoneCall {

    final static double RATE=0.02;
     IncomingPhoneCall(String phoneNumber){
        super(phoneNumber);
        setPrice();
    }
    public void setPrice() {
        price = 0.02;
    }
     void info(){
        System.out.println("Incoming phone call"+getPhoneNumber()+
                " "+RATE+" per call.Total is $"+getPrice());
    }
      public String getPhoneNumber()
      {
          return phoneNumber;
      }
      public double getPrice()
      {
          return price;
      }

}
class OutgoingPhoneCall extends PhoneCall {

    final static double RATE = 0.04;
    private int minutes;
     OutgoingPhoneCall(String phoneNumber, int minutes){
        super(phoneNumber);
        this.minutes = minutes;
        setPrice();;
    }
    public void setPrice() {
        price = 0.04;
    }
    void info() {
        System.out.println("Outgoing phone call " + getPhoneNumber() + " "
                + RATE + " per minute at " + minutes + " minutes. Total is $" + price*minutes);
    }
     public String getPhoneNumber()
     {
         return phoneNumber;
     }
     public double getPrice()
     {
         return price;
     }

}


public class DemoPhoneCalls {
public static void main(String [] args) {

    IncomingPhoneCall incomingPhoneCall=new IncomingPhoneCall("310-332-0908");
    OutgoingPhoneCall outgoingPhoneCall=new OutgoingPhoneCall("310-000-0102",20);

    incomingPhoneCall.info();
    outgoingPhoneCall.info();
 }
}