java 求三角形面积

以下是Java求三角形面积的代码示例：

public class Triangle {
    private double x1, y1, x2, y2, x3, y3; // 三角形三个点的坐标
    private double area; // 三角形的面积

    public Triangle(double x1, double y1, double x2, double y2, double x3, double y3) {
        this.x1 = x1;
        this.y1 = y1;
        this.x2 = x2;
        this.y2 = y2;
        this.x3 = x3;
        this.y3 = y3;
    }

    // 计算三角形面积的方法
    public void calculateArea() {
        double a = Math.sqrt(Math.pow(x1 - x2, 2) + Math.pow(y1 - y2, 2));
        double b = Math.sqrt(Math.pow(x2 - x3, 2) + Math.pow(y2 - y3, 2));
        double c = Math.sqrt(Math.pow(x3 - x1, 2) + Math.pow(y3 - y1, 2));
        double s = (a + b + c) / 2;
        area = Math.sqrt(s * (s - a) * (s - b) * (s - c));
    }

    // 输出三角形坐标和面积的方法
    public void print() {
        System.out.println("(" + x1 + "," + y1 + ") (" + x2 + "," + y2 + ") (" + x3 + "," + y3 + ")");
        System.out.println("area=" + area);
    }

    public static void main(String[] args) {
        Triangle tri = new Triangle(1, 1, 4, 1, 4, 5);
        tri.calculateArea();
        tri.print();
    }
}