问答题
【说明】一条直线是由两个点组成的，代码如下。
public class Point
{
private int x, y; //coordinate
public Point (int x, int y)
{{{U}} (1) {{/U}}=x;{{U}} (2) {{/U}};}
public int GetX()
{ return x; }
public int GetY()
{ return y; }
}
class Line //line segment
{
private{{U}} (3) {{/U}}; //extremc points
Line (Point a, Point b) //constructor
{ p1 ={{U}} (4) {{/U}};
p2={{U}} (5) {{/U}};
}
public double Length() {
return Math.sqrt (Math.pow (p2.GetX()-pl.GetX(),2)
+Math.pow (p2.GetY()-p1.GetY(),2)) ;
}
}