1 files changed, 106 insertions, 0 deletions
diff --git a/labb8/lib/StanfordCPPLib/direction.cpp b/labb8/lib/StanfordCPPLib/direction.cpp
new file mode 100755
index 0000000..4156d56
--- /dev/null
+++ b/labb8/lib/StanfordCPPLib/direction.cpp
@@ -0,0 +1,106 @@
+/*
+ * File: direction.cpp
+ * -------------------
+ * This file implements the direction.h interface.
+ */
+
+#include "direction.h"
+#include "error.h"
+#include "strlib.h"
+#include "tokenscanner.h"
+using namespace std;
+
+/*
+ * Implementation notes: leftFrom, rightFrom, opposite
+ * ---------------------------------------------------
+ * These functions use the remainder operator to cycle through the
+ * internal values of the enumeration type.  Note that the leftFrom
+ * function cannot subtract 1 from the direction because the result
+ * might then be negative; adding 3 achieves the same effect but
+ * ensures that the values remain positive.
+ */
+
+Direction leftFrom(Direction dir) {
+   return Direction((dir + 3) % 4);
+}
+
+Direction rightFrom(Direction dir) {
+   return Direction((dir + 1) % 4);
+}
+
+Direction opposite(Direction dir) {
+   return Direction((dir + 2) % 4);
+}
+
+/*
+ * Implementation notes: directionToString
+ * ---------------------------------------
+ * The C++ compiler requires the default clause to ensure that this
+ * function always returns a string, even if the direction is not one
+ * of the legal values.
+ */
+
+string directionToString(Direction dir) {
+   switch (dir) {
+    case NORTH: return "NORTH";
+    case EAST: return "EAST";
+    case SOUTH: return "SOUTH";
+    case WEST: return "WEST";
+    default: return "???";
+   }
+}
+
+/*
+ * Implementation notes: <<
+ * ------------------------
+ * This operator must return the stream by reference after printing
+ * the value.  The operator << returns this stream, so the function
+ * can be implemented as a single line.
+ */
+
+std::ostream & operator<<(std::ostream & os, const Direction & dir) {
+   return os << directionToString(dir);
+}
+
+/*
+ * Implementation notes: >>
+ * ------------------------
+ * This implementation uses the TokenScanner to read tokens from the
+ * stream.
+ */
+
+std::istream & operator>>(std::istream & is, Direction & dir) {
+   TokenScanner scanner(is);
+   scanner.ignoreWhitespace();
+   string token = toUpperCase(scanner.nextToken());
+   if (token == "") {
+      dir = Direction(-1);
+   } else if (startsWith("NORTH", token)) {
+      dir = NORTH;
+   } else if (startsWith("EAST", token)) {
+      dir = EAST;
+   } else if (startsWith("SOUTH", token)) {
+      dir = SOUTH;
+   } else if (startsWith("WEST", token)) {
+      dir = WEST;
+   } else {
+      error("Direction: Unrecognized direction " + token);
+   }
+   return is;
+}
+
+/*
+ * Implementation notes: ++
+ * ------------------------
+ * The int parameter in the signature for this operator is a marker used
+ * by the C++ compiler to identify the suffix form of the operator.  Note
+ * that the value after incrementing a variable containing WEST will be
+ * out of the Direction range.  That fact will not cause a problem if
+ * this operator is used only in the for loop idiom for which it is defined.
+ */
+
+Direction operator++(Direction & dir, int) {
+   Direction old = dir;
+   dir = Direction(dir + 1);
+   return old;
+}