View Code of Problem 106

#include<iostream>
#include<string>
#include<cmath>
#include<iomanip>
#include<vector>
#include<cstring>
#include<algorithm>
using namespace std;
int main()
{
	double x1, x2, y1, y2, r;
	while (cin >> x1 >> y1 >> x2 >> y2 >> r)
	{
		double d = sqrt(pow((x1 - x2), 2) + pow((y1 - y2), 2));
		if (x1 == x2 && y1 == y2)
		{
			cout << "重合" << endl;
		}
		else if (d > 2 * r)
		{
			cout << "相离" << endl;
		}
		else if (d == 2 * r)
		{
			cout << "相切" << endl;
		}
		else if (x1 == x2 && y1 == y2)
		{
			cout << "重合" << endl;
		}
		else if (d < 2 * r)
		{
			double co = d / 2.0 / r;
			double jiao =2*acos(co);
			double si = sin(jiao);
			double s = pow(r, 2)*(jiao - si);
			cout << "相交 " << fixed << setprecision(2) << s << endl;
		}
	}

}