Add new arithmetic operators and a copy func

src/coord.cpp

@@ -11,6 +11,10 @@ Coord::Coord()
 	, y(0)
 	{}
 
+Coord Coord::copy() {
+	return Coord(x, y);
+}
+
 int& Coord::operator[](int dimension) {
 	switch (dimension) {
 		case 0:
@@ -29,3 +33,11 @@ Coord Coord::operator+(const Coord& other) {
 Coord Coord::operator-(const Coord& other) {
 	return Coord(this->x - other.x, this->y - other.y);
 }
+
+Coord Coord::operator+=(const Coord& other) {
+	return *this + other;
+}
+
+Coord Coord::operator-=(const Coord& other) {
+	return *this - other;
+}

src/include/coord.h

@@ -9,7 +9,9 @@ class Coord {
 		int& operator[](int);
 		Coord operator+(const Coord&);
 		Coord operator-(const Coord&);
-
+		Coord operator+=(const Coord&);
+		Coord operator-=(const Coord&);
+		Coord copy();
 	private:
 		int x;
 		int y;