Sun tutorials problems

[coltragon]

Hello java programmers :)

I'm learning Java with the help of the tutorials on the Sun website(can't post link because this is my first post)
Now i came at the part of classes, i was not expecting this to be hard. because it looked familar to other programming languages. But it was not that easy...

I made a this:

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

          Bicycle bike1 = new Bicycle();
          Bicycle bike2 = new Bicycle();


bike1.changeCadence(30);
bike1.changeGear(4);
bike1.speedUp(5);
bike1.speedUp(25);
bike1.changeCoolness(100);
bike1.printStates();

bike2.changeCadence(25);
bike2.speedUp(60);
bike2.changeGear(6);
bike2.coolnessUp(150);
bike2.coolnessUp(250);
bike2.printStates();
}
}

when i was trying to compile it it gave me this error a lot of times:

Variable.java:8: cannot find symbol
symbol:method changeCadence(int)
location: class Bycicle 
bike1.changeCadence(50); 
      ^

so i googled this error but i didn't have much result.
than i decided to replace it with the original code from the Sun website.
but still it gave me the same error.
do you know, what i can do?

(sorry for my bad english, i'm just 14 years old and not a native english speaker)

Regards,
Coltragon

[Fubarable]

Your Bicycle class doesn't have any of the methods that it's trying to use. In fact it has no methods in it other than a single static main method.

[coltragon]

oh, first i need to declare the functions?
if i remember correctly you do that like this.

int cadence=2;

am i right?

[Char]

oh, first i need to declare the functions?
if i remember correctly you do that like this.

int cadence=2;

am i right?

no..this is how you put a value to a variable

but are you sure this is whole code?
i believe there should be atleast one more class

or what should your code be doing?

[coltragon]

java.sun.com/docs/books/tutorial/java/concepts/class.htmlWhat Is a Class? (The Java™ Tutorials > Learning the Java Language > Object-Oriented Programming Concepts)[/url]
there is the tutorial, i hope you can help me. but i did not understand evrything because it is written in hard to understand english

[Fubarable]

Here is the link: What Is a Class? (The Java™ Tutorials > Learning the Java Language > Object-Oriented Programming Concepts)

And here is the correct class:

class Bicycle {

       int cadence = 0;
       int speed = 0;
       int gear = 1;

       void changeCadence(int newValue) {
            cadence = newValue;
       }

       void changeGear(int newValue) {
            gear = newValue;
       }

       void speedUp(int increment) {
            speed = speed + increment;   
       }

       void applyBrakes(int decrement) {
            speed = speed - decrement;
       }

       void printStates() {
            System.out.println("cadence:"+cadence+" speed:"+speed+" gear:"+gear);
       }
}

You were confusing the Bicycle class above, with the BicycleDemo class below:

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

          // Create two different Bicycle objects
          Bicycle bike1 = new Bicycle();
          Bicycle bike2 = new Bicycle();

          // Invoke methods on those objects
          bike1.changeCadence(50);
          bike1.speedUp(10);
          bike1.changeGear(2);
          bike1.printStates();

          bike2.changeCadence(50);
          bike2.speedUp(10);
          bike2.changeGear(2);
          bike2.changeCadence(40);
          bike2.speedUp(10);
          bike2.changeGear(3);
          bike2.printStates();
     }
}

One thing you'll learn if you stick with programming is that it is not very forgiving. Precision is paramount.

Much luck and have fun!

[coltragon]

thank you so much that really helped.