diff --git a/c/binary-search/src/binary_search.c b/c/binary-search/src/binary_search.c
index b75ac9c..9720cf1 100644
--- a/c/binary-search/src/binary_search.c
+++ b/c/binary-search/src/binary_search.c
@@ -4,8 +4,7 @@ const int *binary_search(int v, const int *a, size_t size)
 {
     size_t lo, hi, i;
 
-    /* quickly exclude invalid/trivial results :
-     * NULL or empty array, value out of bounds
+    /* early exclude invalid/trivial result: NULL/empty array, value off bounds
      */
     if (!size || !a || v < *a || v > *(a+size-1))
         return NULL;
@@ -22,7 +21,6 @@ const int *binary_search(int v, const int *a, size_t size)
  * https://github.com/braoult/exercism/blob/master/c/templates/GNUmakefile
  */
 #ifdef UNIT_TEST
-#include <stdio.h>
 int main(int ac, char **av)
 {
     int arg=1, *res;
diff --git a/c/binary-search/src/binary_search.h b/c/binary-search/src/binary_search.h
index b89058a..af83713 100644
--- a/c/binary-search/src/binary_search.h
+++ b/c/binary-search/src/binary_search.h
@@ -12,6 +12,7 @@ const int *binary_search(int value, const int *arr, size_t length);
 #include <stdio.h>
 #include <stdlib.h>
 #endif
+
 #ifdef  TESTALL
 #undef  TEST_IGNORE
 #define TEST_IGNORE() {}
diff --git a/c/hamming/src/hamming.c b/c/hamming/src/hamming.c
index 144625a..c4f5301 100644
--- a/c/hamming/src/hamming.c
+++ b/c/hamming/src/hamming.c
@@ -1,14 +1,5 @@
 #include "hamming.h"
 
-/* Note: For explanation on section below, see 'GNUfilename' included in
- * link below :
- * https://exercism.io/my/solutions/103b2f7d92db42309c1988030f5202c7
- */
-#if defined UNIT_TEST || defined DEBUG
-#include <stdio.h>
-#include <stdlib.h>
-#endif
-
 /* test does not include invalid input, but it should, as the subject is
  * about DNA sequence, not ASCII chars sequence :-)
  * exercism test needs only:
@@ -16,22 +7,25 @@
  */
 #define V(p) (*(p)=='A' || *(p)=='C' || *(p)=='G' || *(p)=='T')
 
-int compute(const char *lhs, const char *rhs)
+int compute(const char *l, const char *r)
 {
     int res=0;
-    const char *l=lhs, *r=rhs;
 
     if (!l || !r)
         return -1;
-    for (; V(l) && V(r); ++l, ++r) {
+    for (; V(l) && V(r); ++l, ++r)
         if (*l != *r)
             res++;
-    }
-    return *r || *l? -1: res;
+    return *l || *r? -1: res;
 }
 
+/* See GNUmakefile below for explanation
+ * https://github.com/braoult/exercism/blob/master/c/templates/GNUmakefile
+ */
+#if defined UNIT_TEST
+#include <stdio.h>
+#include <stdlib.h>
 
-#ifdef UNIT_TEST
 int main(int ac, char **av)
 {
     if (ac==3) {
diff --git a/c/hamming/src/hamming.h b/c/hamming/src/hamming.h
index 8e31f0b..52a42c1 100644
--- a/c/hamming/src/hamming.h
+++ b/c/hamming/src/hamming.h
@@ -3,9 +3,8 @@
 
 int compute(const char *lhs, const char *rhs);
 
-/* Note: For explanation on section below, see 'GNUfilename' included in
- * link below :
- * https://exercism.io/my/solutions/103b2f7d92db42309c1988030f5202c7
+/* See GNUmakefile below for explanation
+ * https://github.com/braoult/exercism/blob/master/c/templates/GNUmakefile
  */
 #ifdef  TESTALL
 #undef  TEST_IGNORE