Add check for C++-style comments

Also fix a single instance in sortedarray.h.

Author: fragglet

.github/workflows/make.yml

@@ -23,6 +23,15 @@ jobs:
           echo
           false
         fi
+    - name: Check comment style
+      run: |
+        if grep " //" */*.[ch]; then
+          echo
+          echo "*** C++-style comments were detected in the above lines."
+          echo "*** Please change to use /* ... */ -style comments."
+          echo
+          false
+        fi
 
   build_and_coverage:
     runs-on: ubuntu-latest

src/sortedarray.h

@@ -164,4 +164,4 @@ void sortedarray_clear(SortedArray *sortedarray);
 }
 #endif
 
-#endif // #ifndef ALGORITHM_SORTEDARRAY_H
+#endif /* #ifndef ALGORITHM_SORTEDARRAY_H */