COSC 2
Gareth Beckham
COSCLab3.docx/**
* This is the program driver (where the program starts)
* It is in charge of creating the race and it's participants and telling them to "go" in the race.
* @author vjl8401
*/
public class RaceTrack //driver
{
public final static int raceDuration = 1000; //store the length of the race (can be accessed anywhere in code)
public static void main(String arg[])
{
//Instantiating my object instances
Engine engine = new Engine(67);
Vehicle c1 = new Car(1,engine,2); //this one I'm storing as the base class (vehicle)
Car c2 = new Car(2,new Engine(94),4); //this one I store as the sub class (car). There are differences but they do not come into play here
Truck t1 = new Truck(3,new Engine(87),2,250);
//This is an array
Vehicle[] allVehicles = new Vehicle[3];
//placing the vehicles into an array
allVehicles[0] = c1; //polymorphism ("isa")
allVehicles[1] = c2; //remember just because I store these as vehicles doesn't mean that the
allVehicles[2] = t1; //methods for them has changed. Each still stores its own go method.
//infinite loop (well without the base case it is)
while (true) //this will run until a race participant crosses the finish line (passes raceDuration)
{
int max=0;
//tell the cars to "go" one by one
for (int i=0; i<allVehicles.length;i++) //3 times
{
Vehicle v = allVehicles[i];
v.Go();//polymorphism
System.out.println(v);
max = Math.max(max,v.RaceProgress);
}
System.out.println();
//check to see if someone has won the race
if (max > raceDuration)
{
break;
}
}
System.out.println("We have a winner!!! \n*** Vehicle "+RaceTrack.GetFurthestVehicle(allVehicles)+" ***");
}
//just a helper method to find out which vehicle won the race
public static int GetFurthestVehicle(Vehicle[] allVehicles)
{
int max=0;
int VIN=0;
for (int i=0; i<allVehicles.length;i++)
{
if (max < allVehicles[i].RaceProgress)
{
max = allVehicles[i].RaceProgress;
VIN = allVehicles[i].VIN;
}
}
return VIN;
}
}
class Engine
{
int speed;
public Engine(int speed)
{
this.speed = speed;
}
/**
* This is the original speed modifier (it may need to be redefined)
* @return int random between half the speed and the whole speed
*/
public int SpeedModifier()
{
//returns speed/2 to maxSpeed
return (int)(Math.random()*speed/2)+speed/2;
}
}
//Base class (abstract means that we can't make Vehicles)
//class' responsibility to protect its data/attributes
abstract class Vehicle extends Object
{
//attributes (fields
int passengers;
int VIN;
int RaceProgress;
Engine engine; //storage (association, aggregation, composition)
//Constructors (used to create the objects):
Vehicle(int vin, Engine e)
{
passengers = 1;
RaceProgress = 0;
VIN = vin;
engine = e;
}
/**
* This is the main function that progresses the vehicles through the race
* this should be called each loop of the program (this must be redefined in each
* subclass of vehicle)
*/
abstract public void Go(); //this is correctly coded, the abstract method only has its header, and no body - the body must be overwritten in subclasses
/**
* Part of object. This is invoked when an instance of this class is attempted to be used as a string (like during System.out.println)
*/
public String toString()
{
return "Vehicle: "+VIN+
" Progress: "+RaceProgress;
}
public boolean equals(Object other)
{
return this.VIN == ((Vehicle)other).VIN;
}
public void reset()
{
RaceProgress = 0;
}
}
/**
*
* SubClass of Vehicle
*
*/
class Car extends Vehicle //car "is a" vehicle
{
/**
* Car Constructor (no return specified)
* @param i = (0,100)
* @param passengers
* @param speed
*/
Car(int i, Engine e, int passengers) //Working constructor
{
//super or this
//super(); implied
super(i,e);//calling the constructor in Vehicle
this.passengers = passengers;
}
public String toString()
{
return "Car::"+super.toString();
}
//This is overwriting the super/base classes method
//car satisfies the vehicles Go requirement
public void Go()
{
RaceProgress += engine.SpeedModifier() - 10 * (passengers-1);
}
}
//Another subclass of Vehicle (this is considered a concrete class because it is not abstract)
class Truck extends Vehicle
{
//This is data that exists only in trucks
int towWeight;//special note that vehicle cannot access this. In order for it to do so a
//cast operation must be applied to a valid truck.
Truck(int i, Engine e, int passengers, int towWeight)
{
super(i, e);
this.passengers = passengers;
this.towWeight = towWeight;
}
public String toString()
{
return "Truck::"+super.toString();
}
//truck satisfies the vehicles Go requirement
public void Go()
{
RaceProgress += engine.SpeedModifier() - (0.1f * towWeight);
}
}
