This is a Java Program to find the area of a polygon using slicker method. The algorithm assumes the usual mathematical convention that positive y points upwards. In computer systems where positive y is downwards (most of them) the easiest thing to do is list the vertices counter-clockwise using the “positive y down” coordinates. The two effects then cancel out to produce a positive area.
Here is the source code of the Java Program to Implement Slicker Algorithm that avoids Triangulation to Find Area of a Polygon. The Java program is successfully compiled and run on a Windows system. The program output is also shown below.
//This is a java program to find the area of polygon using Slicker algorithm import java.util.*; class Area_polygon_Slicker { static final int MAXPOLY = 200; static final double EPSILON = 0.000001; static class Point { double x, y; } static class Polygon { Point p[] = new Point[MAXPOLY]; int n; Polygon() { for (int i = 0; i < MAXPOLY; i++) p[i] = new Point(); } } static double area(Polygon p) { double total = 0; for (int i = 0; i < p.n; i++) { int j = (i + 1) % p.n; total += (p.p[i].x * p.p[j].y) - (p.p[j].x * p.p[i].y); } return total / 2; } static public void main(String[] args) { Polygon p = new Polygon(); Scanner sc = new Scanner(System.in); System.out.println("Enter the number of points in Polygon: "); p.n = sc.nextInt(); System.out.println("Enter the coordinates of each point: <x> <y>"); for (int i = 0; i < p.n; i++) { p.p[i].x = sc.nextDouble(); p.p[i].y = sc.nextDouble(); } double area = area(p); if (area > 0) System.out.print("The Area of Polygon with " + p.n + " points using Slicker Algorithm is : " + area); else System.out.print("The Area of Polygon with " + p.n + " points using Slicker Algorithm is : " + (area * -1)); sc.close(); } }
Output:
$ javac Area_polygon_Slicker.java $ java Area_polygon_Slicker Enter the number of points in Polygon: 4 Enter the coordinates of each point: <x> <y> 1 1 1 6 6 6 6 1 The Area of Polygon with 4 points using Slicker Algorithm is : 25.0 Enter the number of points in Polygon: 5 Enter the coordinates of each point: <x> <y> 1 2 4 5 9 8 3 2 1 5 The Area of Polygon with 5points using Slicker Algorithm is : 6.0
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