#include #define Vector Point using namespace std; struct Point { double x; double y; Point(double x, double y) : x(x), y(y) {} bool operator==(const Point &that) const { return this->x == that.x && this->y == that.y; } Point operator-(const Point &that) const { return Point(this->x - that.x, this->y - that.y); } Point operator+(const Point &that) const { return Point(this->x + that.x, this->y + that.y); } }; int main() { double x11, y11, x12, y12, x21, y21, x22, y22; while (scanf("%lf%lf%lf%lf", &x11, &y11, &x12, &y12) != EOF) { scanf("%lf%lf%lf%lf", &x21, &y21, &x22, &y22); Point p1(x11, y11), p2(x12, y12), p3(x21, y21), p4(x22, y22), p5(0, 0); if (p1 == p3) { p5 = p1 + ((p2 - p1) + (p4 - p3)); } else if (p1 == p4) { p5 = p1 + ((p2 - p1) + (p3 - p4)); } else if (p2 == p3) { p5 = p2 + ((p1 - p2) + (p4 - p3)); } else { p5 = p2 + ((p1 - p2) + (p3 - p4)); } printf("%.3lf %.3lf\n", p5.x, p5.y); } return 0; }