add method for distance between two points

src/coord.cpp

 #include "include/coord.h"
 #include <string>
 #include <cmath>
+#include <algorithm>
 
 Coord::Coord(int x, int y)
 	: x(x)
@@ -72,4 +73,8 @@ bool Coord::operator!=(const Coord& other) {
 
 std::string Coord::toString() const{
 	return std::to_string(x) + ", " + std::to_string(y);
-}
\ No newline at end of file
+}
+
+int Coord::distanceTo(const Coord& other) const {
+	return std::max(std::abs(x - other.x), std::abs(y - other.y));
+}

src/include/coord.h

@@ -25,6 +25,8 @@ class Coord {
 		Coord asScreen();
 		Coord copy();
 		std::string toString() const;
+		// maximum distance in either dimension
+		int distanceTo(const Coord&) const;
 	private:
 		int x, y;
 		static const int MAPX = 0, MAPY = 2;