View Code of Problem 106

#include<iostream>
#include<cmath>
using namespace std;

int  main(){
    double x1,y1,x2,y2,r;
    while (scanf("%lf %lf %lf %lf %lf",&x1,&y1,&x2,&y2,&r)!=EOF){
        double d=sqrt(pow(fabs(x1-x2),2)+pow(fabs(y1-y2),2));
        if(d==2*r){
            cout<<"相切"<<endl;
        }
        else if(d==0){
            cout<<"重合"<<endl;
        }
        else if(d>2*r){
            cout<<"相离"<<endl;
        }
        else{
            double ang1=acos(d/(2*r));
            printf("相交 %.2f\n",2*ang1*r*r-r*d*sin(ang1));
        }
    }
}