Finished preprocessor theory section

c_modern_approach/Preprocessor/defined.c

@@ -0,0 +1,12 @@
+#include <stdio.h>
+#define DEBUG 1
+
+int main()
+{
+  #if defined (DEBUG)
+  printf("DEBUG defined");
+  #else
+  printf("DEBUG not defined");
+  #endif
+  return 0;
+}

c_modern_approach/Preprocessor/error.c

@@ -0,0 +1,21 @@
+#include <stdio.h>
+// #define DEBUG 1
+
+int main() {
+#ifdef DEBUG
+  printf("All good, DEBUG is initialized");
+#else
+#error Debug is not initiated!
+#endif
+  return 0;
+}
+
+// #error identifier blocks code compilation if compiler reached it.
+// For example code above will not compile if DEBUG is not initiated.
+//
+// error.c: In function ‘main’:
+// error.c:8:2: error: #error Debug is not initiated!
+//     8 | #error Debug is not initiated!
+//       |  ^~~~~
+// make: *** [Makefile:14: main] Error 1
+

c_modern_approach/Preprocessor/ifdef_ifndef.c

@@ -0,0 +1,13 @@
+#include <stdio.h>
+// #define DEBUG 1
+// #ifdef identifier is similar to #if defined(identifier)
+//
+// #ifndef is just opposite of #ifdef
+int main() {
+#ifdef DEBUG
+  printf("DEBUG defined!");
+#else
+  printf("DEBUG NOT defined!");
+#endif
+  return 0;
+}

c_modern_approach/Preprocessor/ifendif.c

@@ -0,0 +1,11 @@
+#include <stdio.h>
+#define DEBUG 0
+
+int main() 
+{
+  printf("Hello ");
+  #if DEBUG
+  printf("debug ");
+  #endif
+  printf("World!");
+}

c_modern_approach/Preprocessor/pragma.c

@@ -0,0 +1,12 @@
+/*
+ * #pragma tokens
+ * Используется когда программы слишком большие и надо воспользоваться какими-то
+ * особыми фичами компилятора.
+ */
+
+#include <stdio.h>
+#pragma data(heap_size = > 1000, stack_size = > 2000)
+int main() 
+{
+  return 0;
+}