Thread: Using variables from different methods?

If you want to make a local variable in one method available in another method, you must either pass it as a method parameter (you can have as many of these as you want0, or return it to the calling method (every method is limited to at most 1 of these).

To declare what parameters a method should expect:

public void someMethod(Type1 param1, Type2 param2) // etc. etc.
{
}

Where Type1/2 is the type of the parameter variable, and param1/2 is the name you will assign to a new variable that will take on the value of the variable passed to the method.

ex.:

public void add(int a, int b)
{
     System.out.println("a + b = " + (a+b));
}

In returning a value, you only need to specify the type that is being returned. You replace the "void" with the type you want. Void is just considered the absence of a type (aka. nothing is returned). Once you declare your method to return a certain type, it MUST return some valid value of that type in all possible branches of execution the program can take.

public int add(int a, int b)
{
     return a + b;
}

In your case, there are a few possible things you can do because you have 2 values that need to be returned.
Choice 1: Create two methods, one that returns the center X coordinate, and the other that returns the bottom Y coordinate.

int centerX = findCenterX();
int centerY = findBottom();

public int findCenterX()
{
     int x = getWidth();
     return x / 2;
}
public int findBottomY()
{
      return getHeight();
}

Choice 2: Create an object that holds both values (or use the Dimension class, doesn't matter), then return that one object.

public class Dim
{
     // ignore my bad example by declaring these public :P
     public int x, y;
     public Dim(int x, int y)
     {
          this.x = x;
          this.y = y;
     }
}

public Dim findCenter()
{
	int x = getWidth();
	int y = getHeight();
	int center = x/2;
	int bottom = y;
	return new Dim(center, bottom);
}

Choice 3: Have either a class instance or static variable.

public class Pyramid extends GraphicsProgram
{
     int centerX, bottomY;
 
     public void findCenter()
     {
          this.centerX = getWidth() / 2;
          this.bottomY = getHeight();
     }
}

Remember, you must pass the arguments to the function. It is perfectly legal to pass any type of parameter to a method so long as that method is declared to accept that type of object (see above examples for how to do this).

A second item you'll need to take into account is because you do have a Dim object, you must reference x and y from that object. This is done using the "." operator (dot operator).

Dim someDimension = new Dim(1,0);
System.out.println("The center x coordinate is " + someDimension.x);
System.out.println("The center y coordinate is " + someDimension.y);