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;
}