Fix minor compiler warnings

include/linkahead/connection.h

@@ -173,7 +173,7 @@ private:
 
   static ConnectionManager mInstance;
 
-  inline ConnectionManager() {};
+  ConnectionManager() = default;
 
   auto mHasConnection(const std::string &name) const -> bool;
 

src/linkahead/result_table.cpp

@@ -104,8 +104,7 @@ auto ResultTable::GetRows() const noexcept -> RowIterator { return RowIterator(t
 ResultTable::RowIterator::RowIterator(const ResultTable *result_table_param, int index)
   : current_index(index), result_table(result_table_param) {}
 
-ResultTable::RowIterator::RowIterator(const RowIterator &other)
-  : current_index(other.current_index), result_table(other.result_table) {}
+ResultTable::RowIterator::RowIterator(const RowIterator &other) = default;
 
 auto ResultTable::RowIterator::size() const noexcept -> int {
   return this->result_table->delegate->wrapped->data_rows_size();
@@ -143,8 +142,7 @@ auto ResultTable::GetHeader() const noexcept -> HeaderIterator { return HeaderIt
 ResultTable::HeaderIterator::HeaderIterator(const ResultTable *result_table_param, int index)
   : current_index(index), result_table(result_table_param) {}
 
-ResultTable::HeaderIterator::HeaderIterator(const HeaderIterator &other)
-  : current_index(other.current_index), result_table(other.result_table) {}
+ResultTable::HeaderIterator::HeaderIterator(const HeaderIterator &other) = default;
 
 auto ResultTable::HeaderIterator::size() const noexcept -> int {
   return this->result_table->delegate->wrapped->header().columns_size();

src/linkahead/utility.cpp

@@ -128,9 +128,8 @@ auto _load_json_file(const path &json_file) -> value {
   stream.exceptions(std::ios_base::badbit);
 
   stream_parser parser;
-  auto result = std::string();
   auto buffer = std::string(buffer_size, '\0');
-  while (stream.read(&buffer[0], buffer_size)) {
+  while (stream.read(buffer.data(), buffer_size)) {
     parser.write(buffer.c_str(), stream.gcount());
   }
   parser.write(buffer.c_str(), stream.gcount());

test/test_entity.cpp

@@ -737,11 +737,11 @@ TEST(test_entity, test_remove_property) {
   entity.AppendProperty(property10);
   ASSERT_EQ(entity.GetProperties().size(), 9);
 
-  std::cout << "[" << std::endl;
+  std::cout << "[" << "\n";
   for (int i = 0; i < 9; i++) {
     std::cout << "  " << entity.GetProperties().at(i).GetName() << ",\n";
   }
-  std::cout << "]" << std::endl;
+  std::cout << "]" << "\n";
 
   for (int i = 0; i < 3; i++) {
     auto name = "PROPERTY-" + std::to_string(i);