feat(Week09): Add solutions

2 files changed, 91 insertions, 0 deletions

diff --git a/Week09/Exercise04/Rover.cpp b/Week09/Exercise04/Rover.cpp
new file mode 100644
index 0000000..dc311c7
--- /dev/null
+++ b/Week09/Exercise04/Rover.cpp
@@ -0,0 +1,64 @@
+#include "Rover.h"
+#include <cmath>
+
+// Използваме полярни координати, за да опишем посоките.
+// С други думи, използваме ъгъл, такъв че (1,0) е на 0 градуса (радиана),
+// (0,1) е на 90 градуса, (-1,0) е на 180 градуса и (0,-1) е на 270 градуса.
+// Така ако знаем посоката напред, посоката на ляво е на 90 градуса обратно
+// на часовниковата стрелка от ъгъла, който описва посоката "напред".
+// Аналогично, посоката на ляво е на 90 градуса по часовниковата стрелка от
+// ъгъла, който описва посоката "напред".
+
+void Rover::moveDistByAngle(double dist, double angle) {
+	// https://en.wikipedia.org/wiki/Polar_coordinate_system#Converting_between_polar_and_Cartesian_coordinates
+	this->x += dist * cos(angle);
+	this->y += dist * sin(angle);
+}
+
+Rover::Rover() {
+	x = y = 0;
+	forward = M_PI_2;
+}
+
+Rover& operator<(double dist, Rover& rover) {
+	rover.moveDistByAngle(dist, rover.forward + M_PI_2);
+	return rover;
+}
+
+Rover& Rover::operator>(double dist) {
+	this->moveDistByAngle(dist, this->forward - M_PI_2);
+	return *this;
+}
+
+Rover& Rover::operator^(double dist) {
+	this->moveDistByAngle(dist, this->forward);
+	return *this;
+}
+
+Rover& operator<<(double degrees, Rover& rover) {
+	rover.forward += degrees / 180.0 * M_PI;
+	return rover;
+}
+
+Rover& Rover::operator>>(double degrees) {
+	this->forward -= degrees / 180.0 * M_PI;
+	return *this;
+}
+
+std::ostream& operator<<(std::ostream& ostr, const Rover& rover) {
+	double forwardUnitX = cos(rover.forward), forwardUnitY = sin(rover.forward);
+	ostr << "Rover at (" << rover.x << ',' << rover.y
+		<< "), looking direction (" << forwardUnitX << ',' << forwardUnitY << ')'
+		<< std::endl;
+	return ostr;
+}
+
+std::istream& operator>>(std::istream& istr, Rover& rover) {
+	// Очакваме координат, който описва посоката "напред"
+	// Например (0,1)
+	double forwardUnitX, forwardUnitY;
+	istr >> rover.x >> rover.y >> forwardUnitX >> forwardUnitY;
+	// https://en.wikipedia.org/wiki/Polar_coordinate_system#Converting_between_polar_and_Cartesian_coordinates
+	rover.forward = atan2(forwardUnitY, forwardUnitX);
+	return istr;
+}
diff --git a/Week09/Exercise04/Rover.h b/Week09/Exercise04/Rover.h
new file mode 100644
index 0000000..4286f06
--- /dev/null
+++ b/Week09/Exercise04/Rover.h
@@ -0,0 +1,27 @@
+#ifndef _ROVER
+#define _ROVER
+
+#include <ostream>
+#include <istream>
+
+class Rover {
+	double x;
+	double y;
+	double forward;
+
+	void moveDistByAngle(double dist, double angle);
+
+public:
+	Rover();
+
+	friend Rover& operator<(double dist, Rover& rover);
+	Rover& operator>(double dist);
+	Rover& operator^(double dist);
+	friend Rover& operator<<(double degrees, Rover& rover);
+	Rover& operator>>(double degrees);
+
+	friend std::ostream& operator<<(std::ostream& ostr, const Rover& rover);
+	friend std::istream& operator>>(std::istream& istr, Rover& rover);
+};
+
+#endif /* _ROVER */