View Code of Problem 106

#include<stdio.h>
#include<math.h> 
int main()
{
	double x1,y1,x2,y2,r;
	while(scanf("%lf %lf %lf %lf %lf",&x1,&y1,&x2,&y2,&r)!=EOF)
	{
		if(sqrt(pow(y2-y1,2)+pow(x2-x1,2))==0)
		printf("重合\n");
		else if(sqrt(pow(y2-y1,2)+pow(x2-x1,2))==2*r)
		{
			printf("相切\n"); 
		} 
		 else if(sqrt(pow(y2-y1,2)+pow(x2-x1,2))>2*r)
		{
		 	printf("相离\n"); 	
		}
		else if(sqrt(pow(y2-y1,2)+pow(x2-x1,2))>0&&sqrt(pow(y2-y1,2)+pow(x2-x1,2))<2*r)
		{
			double l=sqrt(pow(y2-y1,2)+pow(x2-x1,2));
			double ang1=acos((r*r+l*l-r*r)/2/(l*r));
        	double ang2=acos((r*r+l*l-r*r)/2/(l*r));
       		double area=ang1*r*r*2-sin(ang1)*r*l;
   			printf("相交 %.2lf\n",area);
		 } 
	}
		
}