三角形外接圆圆心 算法 删改版

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//求三角形外接圆圆心坐标

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struct Point{

double x;

double y;

};

Point circle_center(Point pt[3])

{

double x1,x2,x3,y1,y2,y3;

double x = 0;

double y = 0;

x1 = pt[0].x;

x2 = pt[1].x;

x3 = pt[2].x;

y1 = pt[0].y;

y2 = pt[1].y;

y3 = pt[2].y;

x=((y2-y1)*(y3*y3-y1*y1+x3*x3-x1*x1)-(y3-y1)*(y2*y2-y1*y1+x2*x2-x1*x1))/(2*(x3-x1)*(y2-y1)-2*((x2-x1)*(y3-y1)));

y=((x2-x1)*(x3*x3-x1*x1+y3*y3-y1*y1)-(x3-x1)*(x2*x2-x1*x1+y2*y2-y1*y1))/(2*(y3-y1)*(x2-x1)-2*((y2-y1)*(x3-x1)));

Point center;

center.x = x ;

center.y = y ;

return center;

}