/* Point.java */

/* simple class definition--we try to model the idea of a 
geometric point; the class contains two data members
(corresponding to the x and y coordinates of the point; these
are defined in terms of the primitive Java type "int" (analogous
to int in C) and a set of methods that set and retrieve the
values of the data members; the data members can only be accessed
by methods in this class, the methods can be executed anywhere;
this separate of "implementation" and "interface" is commonly
seen; so too are these sorts of "accessor" or "getter" and
"setter" methods; this class isn't an executable program in its
own right */

/* class definitions begin "[access-specifier--commonly 'public',
as in this case] class [classname]", followed by the body of the 
class definition within curly braces */
public class Point {
  /* the data members; declarations take the form "[access-specifier]
  [data-type] name"; we'll discuss access-specifiers at length
  later on, they include public (accessible without restriction),
  private (accessible only from within this class), protected, and
  there's also a default access rule associated with the absence of
  an explicit specifier */ 
  private int x, y;

  /* and then here are the methods; all methods in Java have the
  form "[access-specifier] [return-type] [method-name]([parameter
  list])"; the set* methods all accept input parameters and use them
  to set the values of the data members ("=", as in C, is the
  assignment operator in Java); when a method doesn't compute and
  return a specific value, the return type is marked as "void" in
  the method definition; the parameter list for a method consists of
  zero or more comma-separated pairs, the first term of which gives
  the type of a parameter and the second a local name for it */
  public void setPoint(int xVal, int yVal) {
    x = xVal;
    y = yVal;
  }
  public void setX(int n) { x = n; }
  public void setY(int n) { y = n; }
  
  /* to return a value from a method you say "return [expression]";
  the value of the expression must be of the same type that's given
  as the return type of the method in its signature */ 
  public int getX() { return x; }
  public int getY() { return y; }
}