diff --git a/k&r/04-funcs-and-prog-struct/04-calc/04-calc.c b/k&r/04-funcs-and-prog-struct/04-calc/04-calc.c
index 1929fa7..1472e8e 100644
--- a/k&r/04-funcs-and-prog-struct/04-calc/04-calc.c
+++ b/k&r/04-funcs-and-prog-struct/04-calc/04-calc.c
@@ -9,10 +9,6 @@
 
 /* --------- ERROR MESSAGES */
 #define printerr(format, ...) printf("error: " format "\n", ##__VA_ARGS__)
-#define ZERODIV_ERR "zero divisor"
-#define DOMAIN_ERR "operand not in domain [%d, %d]"
-#define NEG_ERR "negative operand %g"
-#define FULL_STACK_ERR  "stack full, can't push %g"
 #define UNKNOWN_TOKEN_ERR "unknown token %s"
 #define VAR_NOT_SET_ERR "variable %c has no value"
 
diff --git a/k&r/04-funcs-and-prog-struct/04-calc/04-glob-stack.h b/k&r/04-funcs-and-prog-struct/04-calc/04-glob-stack.h
index 5cb6754..89a77fa 100644
--- a/k&r/04-funcs-and-prog-struct/04-calc/04-glob-stack.h
+++ b/k&r/04-funcs-and-prog-struct/04-calc/04-glob-stack.h
@@ -3,8 +3,10 @@
 #define STACK_H
 #define printerr(format, ...) printf("error: " format "\n", ##__VA_ARGS__)
 
+/* ERROR MESSAGES */
 #define EMPTY_STACK_ERR "stack empty" 
 #define SHORT_STACK_ERR "not enough elements on stack"
+#define FULL_STACK_ERR  "stack full, can't push %g"
 
 #ifndef MAX_STACK
 #define MAX_STACK 100
diff --git a/k&r/04-funcs-and-prog-struct/04-calc/04-tokens.h b/k&r/04-funcs-and-prog-struct/04-calc/04-tokens.h
index 11cc0d0..8d1c76f 100644
--- a/k&r/04-funcs-and-prog-struct/04-calc/04-tokens.h
+++ b/k&r/04-funcs-and-prog-struct/04-calc/04-tokens.h
@@ -2,6 +2,13 @@
 
 #define TOKENS_H
 #include <math.h>
+#define printerr(format, ...) printf("error: " format "\n", ##__VA_ARGS__)
+
+/* ERROR MESSAGES */
+#define ZERODIV_ERR "zero divisor"
+#define DOMAIN_ERR "operand not in domain [%d, %d]"
+#define NEG_ERR "negative operand %g"
+
 /* --------- CALCULATOR FUNCTION TYPES */
 /* the following macros allow us to call native c constructs 
  * in a declarative style */
@@ -89,4 +96,5 @@
     OPERATORS \
     MATH_H_BINDINGS
 
+#undef printerr
 #endif // TOKENS_H