範例程式碼 uva10242

//uva10242
#include <iostream>
#include <ios>
#include <iomanip>
using namespace std;

int main() {
	double x1, y1, x2, y2, x3, y3, x4, y4, x, y;
	while (cin >> x1 >> y1 >> x2 >> y2 >> x3 >> y3 >> x4 >> y4) {
		if (x1 == x3 && y1 == y3) {
			x = x2 + x4 - x1;
			y = y2 + y4 - y1;
		}
		else if (x1 == x4 && y1 == y4) {
			x = x2 + x3 - x1;
			y = y2 + y3 - y1;
		}
		else if (x2 == x3 && y2 == y3) {
			x = x1 + x4 - x2;
			y = y1 + y4 - y2;
		}
		else {
			x = x1 + x3 - x2;
			y = y1 + y3 - y2;
		}

		cout << fixed << setprecision(3) << x << " " << fixed << setprecision(3) << y << endl;
	}


	return 0;
}