创建Java Car类

Question

我正在用另一个单独的驱动类做一个类。汽车类别是由汽车租赁公司存储有关汽车的信息，如汽车的制造、型号和登记号码，这样我就可以使用驾驶员类输入新车辆，检查一辆汽车是否出租，是否不可用，如果租用，则检查租用人的姓名。

我的汽车课用的方法：

public class Car {

private String Make;
private String Model;
private int RegistrationNum;

public Car(String Make, String Model, String RegN){
    //Constructor,
    //stores the make, model and registration number of the new car
    //sets its status as available for hire.
    Make = "";
    Model = "";
    RegN = "";

}

public String getMake(){
    return Make;

}

public String getModel(){
    return Model;

}

public boolean hire(String newHirer){

    {
  //Hire this car to the named hirer and return true. 

        return true;
    }
  //Returns false if the car is already out on hire.



}

public boolean returnFromHire(){

    {
 //Receive this car back from a hire and returns true.
        return true;
    }

 //Returns false if the car was not out on hire     


}

public int getRego(){


 //Accessor method to return the car’s registration number      

    RegistrationNum++;
    return RegistrationNum;
    }



public boolean hireable(){
 //Accessor method to return the car’s hire status.     



    {
 //returns true if car available for hire           
    return true;    
    }
}

public String toString(){
 //return car details as formatted string
 //output should be single line containing the make model and reg number
 //followed by either "Available for hire" or "On hire to: <name>"


    return "Vehicle ID number: "+ getRego()+"-"+"Make is: "+ getMake()+"-"+"Model is: "+getModel();


}


}

以下是我的驾驶课程：

  import java.util.*;
  public class CarDriver {
  static Car car1;

public static void main(String[] args) {
    // TODO Auto-generated method stub
    Scanner scan = new Scanner(System.in);


{
    System.out.println("Make?");
    String Make=scan.nextLine();
    System.out.println("Model");
    String Model=scan.nextLine();
    System.out.println("Registration number?");
    String RegNum=scan.nextLine();

    car1 = new Car(Make,Model,RegNum);


    System.out.println("What you input :");

    System.out.println(car1.toString());
}}

 }

我的产出：

Make?
carmake
Model
carmodel
Registration number?
12345t
What you input :
Vehicle ID number: 1-Make is: null-Model is: null

问题：

1. 无法理解如何将布尔方法的伪代码转换为java代码
2. 无法连接驱动程序类来存储我输入的信息，如模型、制造和注册编号

。

Answer 1

第二位

将构造函数更改为此构造函数：

public Car(String Make, String Model, String RegN){
    this.Make = Make;
    this.Model= Model;
    this.RegN = RegN;
}

您以前的构造器有一个问题，基本上您所做的就是获取构造函数参数，并将它们全部设置为"“(空字符串)，您不想这样做。要将参数值赋值给实例字段。如果您想访问实例字段，就必须使用关键字这个。

public Car(String Make, String Model, String RegN){
//Constructor,
//stores the make, model and registration number of the new car
//sets its status as available for hire.
Make = "";
Model = "";
RegN = "";

}

Answer 2

第一:为了检索关于“这辆车是谁租来的”或“哪个司机租了这辆车”的信息，您必须先存储该信息。您会使用什么数据类型？(请记住这是“家庭作业”，我认为最好不要给我答案)。

P.S:对于变量和非静态/最终属性，最好使用非大写标识符。

Answer 3

正如我在代码中所看到的，您没有在构造函数中设置Car实例的任何字段。你应该写这样的字：

public Car(String Make, String Model, String RegN){
    //Constructor,
    //stores the make, model and registration number of the new car
    //sets its status as available for hire.
    this.Make = Make;
    this.Model = Model;
    this.RegN = RegN;
}