Makes all samples compile with -Wall -Wshadow -Werror.

samples/sample2.cc

@@ -36,21 +36,21 @@
 #include <string.h>
 
 // Clones a 0-terminated C string, allocating memory using new.
-const char * MyString::CloneCString(const char * c_string) {
-  if (c_string == NULL) return NULL;
+const char* MyString::CloneCString(const char* a_c_string) {
+  if (a_c_string == NULL) return NULL;
 
-  const size_t len = strlen(c_string);
-  char * const clone = new char[ len + 1 ];
-  memcpy(clone, c_string, len + 1);
+  const size_t len = strlen(a_c_string);
+  char* const clone = new char[ len + 1 ];
+  memcpy(clone, a_c_string, len + 1);
 
   return clone;
 }
 
 // Sets the 0-terminated C string this MyString object
 // represents.
-void MyString::Set(const char * c_string) {
+void MyString::Set(const char* a_c_string) {
   // Makes sure this works when c_string == c_string_
-  const char * const temp = MyString::CloneCString(c_string);
+  const char* const temp = MyString::CloneCString(a_c_string);
   delete[] c_string_;
   c_string_ = temp;
 }