I saw this code
class BinTree1 implements BinTree{
Object val;
BinTree1 left, right;
// abstr(null) = E
// abstr (val, left, right) =
// N((abstr left) val (abstr right))
public BinTree1 (BinTree1 l, Object o, BinTree1 r){
val = o;
left = l;
right = r;
}
public Object val() {
return val;
}
I wonder what this implements means? I was searching the web, but all I found was something about interfaces...