View Code of Problem 106

#include<stdio.h>
#include<math.h>
int main()
{
    double x1,y1,x2,y2,r;
    double dist;
    while(~scanf("%lf%lf%lf%lf%lf",&x1,&y1,&x2,&y2,&r)){
        dist=sqrt((x1-x2)*(x1-x2)+(y1-y2)*(y1-y2));
        if(dist==0)printf("重合\n");
        else if(dist==2*r)printf("相切\n");
        else if(dist>2*r)printf("相离\n");
        else {
            printf("相交 ");
            double s,angle;
            angle=2.0*acos(dist/2.0/r);
            s=r*r*angle/2*2-r*sin(angle/2)*dist;//两个扇形减去菱形
            printf("%.2lf\n",s);
        }
    }
	return 0;
}