Fix writeCommentBeforeValue() iter deref

fixes #649

Author: cdunn2001

src/lib_json/json_writer.cpp

@@ -582,7 +582,7 @@ void StyledWriter::writeCommentBeforeValue(const Value& root) {
   while (iter != comment.end()) {
     document_ += *iter;
     if (*iter == '\n' &&
-       (iter != comment.end() && *(iter + 1) == '/'))
+       ((iter+1) != comment.end() && *(iter + 1) == '/'))
       writeIndent();
     ++iter;
   }
@@ -798,7 +798,7 @@ void StyledStreamWriter::writeCommentBeforeValue(const Value& root) {
   while (iter != comment.end()) {
     *document_ << *iter;
     if (*iter == '\n' &&
-       (iter != comment.end() && *(iter + 1) == '/'))
+       ((iter+1) != comment.end() && *(iter + 1) == '/'))
       // writeIndent();  // would include newline
       *document_ << indentString_;
     ++iter;
@@ -1086,7 +1086,7 @@ void BuiltStyledStreamWriter::writeCommentBeforeValue(Value const& root) {
   while (iter != comment.end()) {
     *sout_ << *iter;
     if (*iter == '\n' &&
-       (iter != comment.end() && *(iter + 1) == '/'))
+       ((iter+1) != comment.end() && *(iter + 1) == '/'))
       // writeIndent();  // would write extra newline
       *sout_ << indentString_;
     ++iter;