All,
I'm going through the Friedman & Felleisen book "A Little Java, A Few Patterns". I'm trying to type the examples in DrJava, but I'm getting some errors. I'm a beginner, so I might be making rookie mistakes.
Here is what I have set-up:
public class ALittleJava {
//ABSTRACT CLASS POINT
abstract class Point {
abstract int distanceToO();
}
class CartesianPt extends Point {
int x;
int y;
int distanceToO(){
return((int)Math.sqrt(x*x+y*y));
}
CartesianPt(int _x, int _y) {
x=_x;
y=_y;
}
}
class ManhattanPt extends Point {
int x;
int y;
int distanceToO(){
return(x+y);
}
ManhattanPt(int _x, int _y){
x=_x;
y=_y;
}
}
}
And on the main's side:
public class Main{
public static void main (String [] args){
Point y = new ManhattanPt(2,8);
System.out.println(y.distanceToO());
}
}
The compiler cannot find the symbols Point and ManhattanPt in the program.
If I precede each by ALittleJava., I get another error in the main, i.e.,
an enclosing instance that contains ALittleJava.ManhattanPt is required
I've tried to find ressources on the 'net, but the book must have a pretty confidential following and I couldn't find much.
Thank you all.
JDelage
