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Car java program help

3 replies on 1 page. Most recent reply: Oct 8, 2009 6:58 AM by Vincent O'Sullivan

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Nay B

Posts: 9
Nickname: blackrose
Registered: Oct, 2009

Car java program help Posted: Oct 5, 2009 3:04 PM
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Hello, I need some help writing 2 classes for a car program. Honestly, I'm kinda lost. Any help would be appreciated. Here's the outline that I was given:

Fields:
yearModel - an integer that holds the car's year model
make - a string that holds the make of the car
speed - an integer that holds the car's current speed

//constructor
the constructor should accept the car's year model and make an arguments. these values should be assigned to the object's yearModel and make fields. The constructor should also assign 0 to the speed field.

Make appropriate accessor methods to get the values and store them in an object's yearModel, make, and speed fields.

*now this is the part i'm truely lost with*

accelerate. the accelerate method should add 5 to the speed field each time it is called

brake. should subtract 5 every time it is called

Demonstrate the class in a program that creates a Car object, and then calls the accelerate method 5 times. After each call to the accelerate method, get the current speed of the car and display it. Then, call the brake method 5 times. After each call to the brake method, get the current speed of the car and display it.
-------------------
I think i have the first half okay-
this is what i have:

public class Car
{
public int yearModel;
public String make;
public int speed;

public Car()
{
yearModel=0;
speed=0;
make="2004 Toyota Echo";
}

public Car(int yearModel, String make, int speed)
{
this.yearModel=yearModel;
this.make=make;
}

public int getYear()
{
return yearModel;
}

public String getMake()
{
return make;
}

public int getSpeed()
{
return speed
}

public int accelerate()
{
speed=speed+5;
return speed;
}

public int break()
{
speed=speed-5;
return speed;
}

public void setYear(int yearValue)
{
this.yearModel=yearValue
}

public void setMake(String make)
{
this.make=make;
}

//not sure how to display twice - telling the person using the program that the car is going 0 mph, then accelerates to 5, then brakes 5mph to 0mph again

public String toString()
{
return "The "+yearModel + make + " is currently going " + speed + "mph.";
}

public static void main(String[]args)
{
Car car1 = new Car(yearModel, make, speed);
}
}//end class Car


Vincent O'Sullivan

Posts: 724
Nickname: vincent
Registered: Nov, 2002

Re: Car java program help Posted: Oct 6, 2009 4:28 PM
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Car car = new Car();
car.accelerate();
System.out.println("Car speed: " + car.getSpeed();
//etc.

Nay B

Posts: 9
Nickname: blackrose
Registered: Oct, 2009

Re: Car java program help Posted: Oct 7, 2009 10:09 PM
Reply to this message Reply
Thank you for your help. :)
I am getting one error message I don't understand:

Car.java --


public class Car
{
public int yearModel;
public String make;
public int speed;

public Car()
{
yearModel=0;
speed=0;
make="2004 Toyota Echo";
}

public Car(int yearModel, String make, int speed)
{
this.yearModel=yearModel;
this.make=make;
}

public int getYear()
{
return yearModel;
}

public String getMake()
{
return make;
}

public int getSpeed()
{
return speed
}

public int accelerate()
{
speed=speed+5;
return speed;
}

public int brake()
{
speed=speed-5;
return speed;
}

public void setYear(int yearValue)
{
this.yearModel=yearValue
}

public void setMake(String make)
{
this.make=make;
}


}//end class Car



and I have
CarDemo.java --


//This is a CarDemo Class

public class CarDemo

{ //Begin Class

public static void main (String args [])

{ //Begin Main Method
//not sure how to display twice - telling the person using the program that the car is going 0 mph, then accelerates to 5, then brakes 5mph to 0mph again

System.out.println("Year Model: " + yearModel);
System.out.println("Make: " + make);
System.out.println("Car Speed: " + speed);
System.out.println("...accelerating...");

public static void main(String args [])
{
Car Car1 = new Car(speed);
Car.accelerate();
Car.accelerate();
Car.accelerate();
Car.accelerat e();
Car.accelerate();
System.out.println("Car speed: " + car.getSpeed());
System.out.println("...braking...");
}

public static void main(String[]args)
{
Car Car1 = new Car(speed);
Car.brake();
Car.brake();
Car.brake();
Car.brake();
Car.brake();
System.out.println("Year Model: " + yearModel);
System.out.println("Make: " + make);
System.out.println("Car speed: " + speed);



} //End of Main Method
} //End of CarDemo Class


The error message I get is:

D:\lotsOfFoldersInBetween\CarDemo.java:37: illegal start of expression
public static void main(String[]args);
^
1 error

Tool completed with exit code 1


please help!!

Vincent O'Sullivan

Posts: 724
Nickname: vincent
Registered: Nov, 2002

Re: Car java program help Posted: Oct 8, 2009 6:58 AM
Reply to this message Reply
The class Car contains two typos (both missing semi-colons) which prevent it compiling.

The class CarDemo is a bit of a mess. I could sort it out for you but you'd be much better of reading this... http://java.sun.com/docs/books/tutorial/java/concepts/class.html ...and then comparing it with your own answer.

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