#include<stdio.h>
#include<math.h>
#define N 2
double mianji(double x1,double y1,double x2,double y2,double x3,double y3);//计算三角形面积
double getLength(double a1,double b1,double a2,double b2);//计算两点之间的距离 
double getShortestLength(double x0,double y0, double x1,double y1,double x2,double y2);//计算点到线段的距离
void main() 
{
    int i,k=0;
    double x[N],y[N],z[N],n,m,chang=0,g=0,h=0,s=0,area2=0,a,b,area,area1;
    for(;;)
    {
    	printf("输入这个点的横坐标和纵坐标：");
    		scanf("%lf %lf",&n,&m);
		printf("输入横坐标:");
    		for(i=0;i<N;i++)
    		scanf("%lf",&x[i]);
    	printf("输入纵坐标：");
    		for(i=0;i<N;i++) 
    		scanf("%lf",&y[i]);
   	 	for(k=0;k<N-1;k++)
  			z[k]=getShortestLength(n,m,x[k], y[k],x[k+1],y[k+1]);
  			z[N-1]=getShortestLength(n,m,x[N-1], y[N-1],x[0],y[0]);
  			chang=z[0];
  		for(k=1;k<N;k++)
  		{
  			if(chang>z[k])
  			chang=z[k];}
  		for(i=0;i<N;i++){
			g+=x[i];
			h+=y[i];}
		a=g/N;
		b=h/N;
		for(i=0;i<N-1;i++){
			area=mianji(x[i],y[i],x[i+1],y[i+1],a,b);
				s+=area;}
			area=mianji(x[0],y[0],x[N-1],y[N-1],a,b);
				s+=area;
		for(i=0;i<N-1;i++){
			area1=mianji(x[i],y[i],x[i+1],y[i+1],n,m);
				area2+=area1;}
			area1=mianji(x[0],y[0],x[N-1],y[N-1],n,m); 
				area2+=area1;
			printf("%lf %lf",s,area2);
				printf("\n");
		if(area2-s<0.001)
			printf("%lf",chang-2*chang);
		else
			printf("%lf",chang);
    }
}
double mianji(double x1,double y1,double x2,double y2,double x3,double y3)//计算三角形面积
{
	double l1,l2,l3,q,e;
	l1=sqrt((x1-x2)*(x1-x2)+(y1-y2)*(y1-y2));
	l2=sqrt((x1-x3)*(x1-x3)+(y1-y3)*(y1-y3));
	l3=sqrt((x2-x3)*(x2-x3)+(y2-y3)*(y2-y3));
	q=(l1+l2+l3)/2;
	e=sqrt(q*(q-l1)*(q-l2)*(q-l3));
	return e;
}
 double getLength(double a1,double b1,double a2,double b2)//计算两点之间的距离
{
	double result;
	result = sqrt((a1-a2)*(a1-a2) + (b1-b2)*(b1-b2)); 
    return result;
} 		
double getShortestLength(double x0,double y0, double x1,double y1,double x2,double y2)//计算点到线段的距离
{
	double a,b,c; // 边长
	double d ; //垂线段长度
	double A,B,C; //斜线表达式系数
	double result ;
	//1 求a,b,c  子功能
	a = getLength(x1,y1,x2,y2);
	b = getLength(x0,y0,x2,y2);
	c = getLength(x0,y0,x1,y1);
	//2 判断 B角是否钝角
    if( a*a + c*c - b*b <= 0) //钝角
	{
		result = c;
	}else{  //锐角
		if( a*a + b*b - c*c <=0 ) //判断 C是否为钝角
		{ 
			result = b;
		}else{  //双锐角
			A = y1-y2;
			B = x2-x1;
			C = x1*y2 - x2*y1;
			d =fabs ( A*x0 + B*y0 +C ) / sqrt( A*A + B*B );
			result = d;
		}
	}
	return result;
}