View Code of Problem 106

#include <stdio.h>
#include <math.h>
#define pai=3.141592;

int main(){
	double x1,y1,x2,y2,r;
	double distance;
	while(scanf("%lf %lf %lf %lf %lf",&x1,&y1,&x2,&y2,&r)!=EOF){
		distance = sqrt(pow((x2-x1),2)+pow((y2-y1),2));
		if(distance==0){
			printf("重合\n");
		}else if(distance==2*r){
			printf("相切\n");
		}else if(distance>2*r){
			printf("相离\n");
		}else if(distance<2*r){
			printf("相交 ");
			double x=acos(distance/(2*r));
			double s=r*r*x/2-distance/2*r*sin(x)/2;
			printf("%.2lf\n",4*s);
		}
	}
}