求两线段交点（Java）

import java.util.Scanner;

class point {
    double x, y;

    point(double x, double y) {
        this.x = x;
        this.y = y;
    }
}

class LinearEquation {
    point a, b, c, d;
    double x, y;

    LinearEquation(point a, point b, point c, point d) {
        this.a = a;
        this.b = b;
        this.c = c;
        this.d = d;
    }

    boolean solve() {
        double denominator = (b.y - a.y) * (d.x - c.x) - (a.x - b.x)
                * (c.y - d.y);
        if (Math.abs(denominator) < 0.000001)
            return false;
        this.x = ((b.x - a.x) * (d.x - c.x) * (c.y - a.y) + (b.y - a.y)
                * (d.x - c.x) * a.x - (d.y - c.y) * (b.x - a.x) * c.x)
                / denominator;
        this.y = -((b.y - a.y) * (d.y - c.y) * (c.x - a.x) + (b.x - a.x)
                * (d.y - c.y) * a.y - (d.x - c.x) * (b.y - a.y) * c.y)
                / denominator;
        if ((x - a.x) * (x - b.x) <= 0 && (y - a.y) * (y - b.y) <= 0
                && (x - c.x) * (x - d.x) <= 0 && (y - c.y) * (y - d.y) <= 0)
            return true;
        return false;
    }
}

public class Main {

    public static void main(String[] args) {
        Scanner cin = new Scanner(System.in);
        while (cin.hasNext()) {
            point p[] = new point[5];
            for (int i = 0; i < 4; i++) {
                double x = cin.nextDouble();
                double y = cin.nextDouble();
                p[i] = new point(x, y);
            }
            LinearEquation ans = new LinearEquation(p[0], p[1], p[2], p[3]);
            if (ans.solve()) {
                System.out.printf("The intersecting point is: (%.2f,%.2f)
",
                        ans.x, ans.y);
            } else
                System.out.println("The two lines do not cross");
        }
    }

}