Question

我的作业需要一些帮助。我努力做到这一点，但我失败了。

我们有一个坐标为三角形：A =（ - 4,4），B =（4，-2），C =（6,6）。一世需要从点P =（x，y）的用户坐标加载然后写入屏幕信息告诉P点是，，或三角形的侧面。

这就是我迄今为止所做的：

class Program
{
    static void Main(string[] args)
    {
        const int x1 = -4, y1 = 4;
        const int x2 = 4, y2 = -2;
        const int x3 = 6, y3 = 6;

        int x0, y0;
        Console.Write("Podaj współrzędną x: ");
        x0 = Convert.ToInt32(Console.ReadLine());
        Console.Write("Podaj współrzędną y: ");
        y0 = Convert.ToInt32(Console.ReadLine());

        double A_AB = (y2 - y1 / x2 - x1);
        double B_AB = (y1 - (y2 - y1 / x2 - x1) * x1);

        double A_AC = (y3 - y1 / x3 - x1);
        double B_AC = (y1 - (y3 - y1 / x3 - x1) * x1);

        double A_BC = (y3 - y2 / x3 - x2);
        double B_BC = (y2 - (y3 - y2 / x3 - x2) * x2);

        if ((y0 > (A_AB * x0 + B_AB) && y0 > (A_AC * x0 + B_AC) && y0 > (A_BC * x0 + B_BC))) Console.WriteLine("Point is inside of the triangle.");
        else if (y0 == (A_AB * x0 + B_AB) || y0 == (A_AC * x0 + B_AC) || y0 == (A_BC * x0 + B_BC)) Console.WriteLine("Point is on the side of the triangle");
        else Console.WriteLine("Point is outside of the triangle.");

        Console.ReadKey(true);
    }
}

有些事情是错误的，因为很难在三角形中占据空间。有人会分析这个吗？我的大脑在燃烧。

感谢。

Answer 1

使用像这样的重心坐标系解决问题：

    public static void Main(string[] args)
    {
        const double x1 = -4, y1 = 4;
        const double x2 = 4, y2 = -2;
        const double x3 = 6, y3 = 6;

        double x, y;
        x = 0;
        y = 1;

        double a = ((y2 - y3)*(x - x3) + (x3 - x2)*(y - y3)) / ((y2 - y3)*(x1 - x3) + (x3 - x2)*(y1 - y3));
        double b = ((y3 - y1)*(x - x3) + (x1 - x3)*(y - y3)) / ((y2 - y3)*(x1 - x3) + (x3 - x2)*(y1 - y3));
        double c = 1 - a - b;

        if (a == 0 || b == 0 || c == 0) Console.WriteLine("Point is on the side of the triangle");
        else if (a >= 0 && a <= 1 && b >= 0 && b<= 1 && c >= 0 && c <= 1) Console.WriteLine("Point is inside of the triangle.");
        else Console.WriteLine("Point is outside of the triangle.");
    }

C＃ - 是三角形的点？

1 个答案: