Printing a sort array

[Jromero]

I have a problem with printing the array



Here is the print out



Picture a vehicle number 1 : What's it's max speed?

100

Picture a vehicle number 2: What's it's max speed?

20

Picture a vehicle number 3: What's it's max speed?

5

Picture a vehicle number 4: What's it's max speed?

5

Picture a vehicle number 5: What's it's max speed?

6

Exception in thread "main" java.lang.Class CastException: Vehicle

at VehicleTest.sor t(VehicleTest.j ava:46)

at VehicleTest.mai n(VehicleTest.j ava:35)





Here is the code:

[

import java.util.Scanner;
 
 
 
class VehicleTest {
 
 
 
      public static void main(String[] args)
 
      {
 
      Vehicle[] vh = new Vehicle[5];
 
 
 
      Scanner scanner = new Scanner(System.in);
 
 
 
      for (int i = 0; i < vh.length; i++)
 
      vh[i] = new Vehicle();
 
 
 
      System.out.println("Picture a vehicle number 1 : What's it's max speed?");
 
      double temp = scanner.nextDouble();
 
      vh[0].setmaxSpeed(temp);
 
      System.out.println("Picture a vehicle number 2: What's it's max speed?");
 
      temp = scanner.nextDouble();
 
      vh[1].setmaxSpeed(temp);
 
      System.out.println("Picture a vehicle number 3: What's it's max speed?");
 
      temp = scanner.nextDouble();
 
      vh[2].setmaxSpeed(temp);
 
      System.out.println("Picture a vehicle number 4: What's it's max speed?");
 
      temp = scanner.nextDouble();
 
      vh[3].setmaxSpeed(temp);
 
      System.out.println("Picture a vehicle number 5: What's it's max speed?");
 
      temp = scanner.nextDouble();
 
      vh[4].setmaxSpeed(temp);
 
 
 
      sort( vh); - line 35 Error problem 
 
      printList(vh);
 
 
 
 
 
      }
 
      public static void sort(Object[]vh){
 
      Object maxSpeed;
 
      int currentmaxIndex;
 
      for (int i = vh.length - 1; i >= 1; i--){
 
      maxSpeed = vh[i];
 
      currentmaxIndex = i;
 
      for (int j = i -1; j>= 0; j--){
 
      if (((Comparable)maxSpeed).compareTo(vh[j]) < 0){  - Line 45 –Error problem 
 
      maxSpeed = vh[j];
 
      currentmaxIndex = j;
 
      }
 
      }
 
      if(currentmaxIndex != i){
 
      vh[currentmaxIndex] = vh[i];
 
      vh[i] = maxSpeed;
 
      }
 
      }
 
      }
 
      public static void printList(Object []vh){
 
      for (int i= 0; i < vh.length; i++)
 
      System.
 
      out.print(vh[i] + " ");
 
      System.
 
      out.println();
 
 
 
      }
 
      }

]

Please help me

[Ganon11]

I would guess that Vehicle has not properly implented the Comparable interface. Have you given it a .compareTo() method that works properly? Also, since you're sorting, you should assume the array is able to be compared (otherwise, there's no way to sort), so you can accept an array of Comparable objects rather than an array of Object objects.

[Jromero]

Here is the code for Vehicle class

Can you explain what you wrote about the comparable array, because I still don't get it

code[


public class Vehicle {


private double maxSpeed;
private double price;
private String color;

public Vehicle() {

}

public Vehicle(double maxSpeed, double price, String color) {
this.maxSpeed = maxSpeed;
this.price = price;
this.color = color;


}

public double getmaxSpeed(){
return maxSpeed;
}

public void setmaxSpeed(dou ble maxSpeed){
this.maxSpeed = maxSpeed ;
}

public double getprice(){
return price;

}


public void setprice(double price){
this.price = price;
}

public String getcolor(){
return color;

}


public void setcolor(String color){
this.color = color;
}

public int compareTo(Objec t o) {
if (getmaxSpeed () > ((Vehicle)o).ge tmaxSpeed())
return 1;
else if (getmaxSpeed () < ((Vehicle)o).ge tmaxSpeed())
return -1;
else
return 0;

}
]

[r035198x]

1.) Please use code tags when posting code
2.) You are trying to cast a Vehicle object to a Comparable object but your Vehicle objects are not Comparable objects. One way of making your Vehicles Comparable is by making the Vehicle class to implement the Comparable interface.

[chaarmann]

Here is the code for Vehicle class

Can you explain what you wrote about the comparable array, because I still don't get it

code[


public class Vehicle {


private double maxSpeed;
private double price;
private String color;

public Vehicle() {

}

public Vehicle(double maxSpeed, double price, String color) {
this.maxSpeed = maxSpeed;
this.price = price;
this.color = color;


}

public double getmaxSpeed(){
return maxSpeed;
}

public void setmaxSpeed(dou ble maxSpeed){
this.maxSpeed = maxSpeed ;
}

public double getprice(){
return price;

}


public void setprice(double price){
this.price = price;
}

public String getcolor(){
return color;

}


public void setcolor(String color){
this.color = color;
}

public int compareTo(Objec t o) {
if (getmaxSpeed () > ((Vehicle)o).ge tmaxSpeed())
return 1;
else if (getmaxSpeed () < ((Vehicle)o).ge tmaxSpeed())
return -1;
else
return 0;

}
]

You should read/learn more about "interface" and "casting".
The priciple is: if you cast a dog to an animal, it works. But if you try to cast a stone to an animal ...

more specific:
If you cast your object to Comparable in your code with

...(Comparable)maxSpeed ...

then your class should implement the Comparable interface, like this:

public class Vehicle implements Comparable

[Jromero]

Thank you so much is working now ....