View Code of Problem 106

#include<stdio.h>
#include<math.h>
int main(){
	double x1,y1,x2,y2,r;
	double d,c,s;
	while(scanf("%lf %lf %lf %lf %lf",&x1,&y1,&x2,&y2,&r)!=EOF){
		d=sqrt((x1-x2)*(x1-x2)+(y1-y2)*(y1-y2));
		if(d==2*r)
			printf("相切\n");
		else if(d>2*r)
			printf("相离\n");
		else if(d==0)
			printf("重合\n");
		else {
			printf("相交 ");
			c=acos(d/2.0/r);
			s=c*r*r-d/2.0*r*sin(c);
			printf("%.2lf\n",2*s) ;
			
		}
	}
	return 0;
}