Notes

notes/2_20/macros.c

+//#include <stdio.h>
+
+#define NPC_SMART   0x00000001
+#define NPC_TELE    0x00000002
+#define NPC_TUNNEL  0x00000004
+#define NPC_ERRATIC 0x00000008
+
+#define MAX_ROOMS 20
+#define NOTHING
+
+#define to_string(s) #s
+
+#define table_element(e) { e, #e }
+struct {int, char * } table[] = {
+	table_element(i);
+	table_element(j);
+};
+
+#define has_characteristic(character, bit)		\
+	((character) & NPC_##bit)
+
+#ifdef NOTHING
+int Idontmatter = MAX_ROOMS;
+#endif
+// Not the best, evalues each argument twice
+#define min(x, y) (x < y ? x : y)
+
+int characteristics = rand() % 16;
+
+// Better, evaluates each argument once and uses those results
+#define max(x, y) ({ \
+	typeof (x) _x = x; \
+	typeof (y) _y = y; \
+	_x > _y ? _x : _y; \
+})
+
+int main(int argc, char *argv[]) {
+	MAX_ROOMS;
+
+	min(3, 4);
+#if 0
+	min(foo(x), bar(x));
+	max(foo(x), bar(x));
+
+	if (10 > min(foo(x), bar(x))) {
+	}
+#endif
+	int x = NOTHING;
+
+	if(has_characteristic(characteristic, SMART)) {
+		// This is a smart monster
+	} else {
+		// This is a not smart monster
+	}
+
+	to_string(Foo);
+
+	return 0;
+}

notes/2_22/jump_table.c

+#include <stdio.h>
+
+// Type func: pointer to function that returns void and takes void
+typedef void (*func)(void);
+
+void zero()
+{
+	printf(__FUNCTION__);
+}
+
+void one()
+{
+	printf(__FUNCTION__);
+}
+
+void two()
+{
+	printf(__FUNCTION__);
+}
+
+void three()
+{
+	printf(__FUNCTION__);
+}
+
+void four()
+{
+	printf(__FUNCTION__);
+}
+
+int main(int argc, char *argv[]) {
+	func table[] = {
+		zero,
+		one,
+		two,
+		three,
+		four
+	};
+
+	int i;
+	for( i = 0; i < 5; i++) {
+		table[i]();
+	}
+
+	return 0;
+}