centralized performance resources

ocw/1/c-primer/preprocess.c

@@ -0,0 +1,21 @@
+// Copyright (c) 2012 MIT License by 6.172 Staff
+
+// All occurences of ONE will be replaced by 1.
+#define ONE 1
+
+// Macros can also behave similar to inline functions.
+// Note that parentheses around arguments are required to preserve order of
+// operations. Otherwise, you can introduce bugs when substitution happens
+
+#define MIN(a, b) ((a) < (b) ? (a) : (b))
+
+int c = ONE, d = ONE + 5;
+int e = MIN(c, d);
+
+#ifndef NDEBUG
+// This code will be compiled only when
+// the macro NDEBUG is not defined.
+// Recall that if clang is passed -DNDEBUG on the command line,
+// then NDEBUG will be defined.
+  if (something) {}
+#endif