The method segments() in the type BruteCollinearPoints is not applicable for the arguments (Point, Point)

Question

I'm trying to modify the code, but got the error listed in the title.Anyone please help.

Error: The method segments() in the type BruteCollinearPoints is not applicable for the arguments (Point, Point)

import java.util.Collections;
import java.util.ArrayList;
import java.util.List;
import edu.princeton.cs.algs4.*;

public class BruteCollinearPoints 
{

   public BruteCollinearPoints(Point[] points)    // finds all line segments containing 4 points
   {
       int N = points.length;
       int i = 0;

       for (int p = 0; p < N; p++) {
            for (int q = p + 1; q < N; q++) {
                double slopeToQ = points[p].slopeTo(points[q]);
                for (int r = q + 1; r < N; r++) {
                    double slopeToR = points[p].slopeTo(points[r]);
                    if (slopeToQ == slopeToR) {
                        for (int s = r + 1; s < N; s++) {
                            double slopeToS = points[p].slopeTo(points[s]);
                            if (slopeToQ == slopeToS) {
                                // Create the list of collinear points and sort them.
                                List<Point> collinearPoints = new ArrayList<Point>(4);
                                collinearPoints.add(points[p]);
                                collinearPoints.add(points[q]);
                                collinearPoints.add(points[r]);
                                collinearPoints.add(points[s]);
                                Collections.sort(collinearPoints);
                                segments(Collections.min(collinearPoints), Collections.max(collinearPoints)); //this is where the error is

                            }
                        }
                    }
                }
            }
       }
   }
   //public           int numberOfSegments();        // the number of line segments
   public LineSegment[] segments()                // the line segments
   {  
        return segments();
   }
}

score 0 · Answer 1 · answered Apr 02 '16 at 15:41

The segments method is defined like this:

public LineSegment[] segments()                // the line segments
{  
    return segments();
}

This means that the method does not take any arguments, yet you are calling it with two arguments:

segments(Collections.min(collinearPoints), Collections.max(collinearPoints));

To fix this you need to call segments method without arguments like this:

segments();

or redefine the method to work with arguments. For example:

public LineSegment[] segments(Point a, Point b)
{  
    // calculate line segments from a to b and return them
}

On a side note, the segments method, as it is defined now, will most certainly not work because it is calling itself recursively without termination condition.

TT-- · Answer 2 · 2017-02-25T02:41:14.533

From your import statements, it seems you're working on a programming assignment from the Algorithms, 4th Edition course called Pattern Recognition. In that course, the method segments() returns an array of type LineSegment[] from another class. You can see it used in the "sample client program" that is provided. Here is a part of that:

for (LineSegment segment : collinear.segments()) {
    StdOut.println(segment);
    segment.draw();
}
StdDraw.show();

In order to actually create a new LineSegment, use something like this:

LineSegment seg = new LineSegment(point1, point2)

For reference, here is the creator that is called in LineSegment.java:

public class LineSegment {
private final Point p;   // one endpoint of this line segment
private final Point q;   // the other endpoint of this line segment

/**
 * Initializes a new line segment.
 *
 * @param  p one endpoint
 * @param  q the other endpoint
 * @throws NullPointerException if either p or q is null
 */
    public LineSegment(Point p, Point q) {
        if (p == null || q == null) {
            throw new NullPointerException("argument is null");
        }
        this.p = p;
        this.q = q;
    }
.
.
.
}

The method segments() in the type BruteCollinearPoints is not applicable for the arguments (Point, Point)

2 Answers2