View Code of Problem 106

#include<bits/stdc++.h>
using namespace std;


int main() {
	float x1, y1, x2, y2, r;
	while (cin >> x1 >> y1 >> x2 >> y2 >> r) {
		if (pow((x2 - x1), 2) + pow((y2 - y1), 2) ==0) {
			cout << "重合" << endl;
		}else if(pow((x2 - x1), 2) + pow((y2 - y1), 2) >4* pow(r, 2)) {
			cout << "相离" << endl;
		}
		else if (pow((x2 - x1), 2) + pow((y2 - y1), 2) == 4*pow(r, 2)) {
			cout << "相切" << endl;
		}
		else {
			cout << "相交 ";
			double a;
			float d = sqrt(pow(fabs(x2 - x1), 2) + pow(fabs(y2 - y1), 2));
			double o = acos(0.5*d / r);
			a = (0.5*o*r*r) * 2;
			a = a - sqrt(r*r - d * d / 4)*d / 2;
			a = a * 2;
			cout << setiosflags(ios::fixed) << setprecision(2) << a << endl;
		}
	}
	return 0;
}