diff --git a/QVectorSearch/mainwindow.cpp b/QVectorSearch/mainwindow.cpp
index 81bd7fd..c37b2a6 100644
--- a/QVectorSearch/mainwindow.cpp
+++ b/QVectorSearch/mainwindow.cpp
@@ -8,6 +8,7 @@
 #include "word_list_generator.h"
 
 #include <thread>
+#include <sstream>
 
 MainWindow::MainWindow(QWidget *parent)
     : QMainWindow(parent), ui(new Ui::MainWindow) {
@@ -37,7 +38,7 @@ void MainWindow::generateWordList() {
   ui->mainStatusBar->showMessage(QString::fromStdString(status_message.str()));
 
   QStringList words;
-  for (auto word : word_list_) {
+  for (const auto &word : word_list_) {
     words.append(QString::fromStdString(word));
   }
 
diff --git a/lib_vector_search/include/timer.h b/lib_vector_search/include/timer.h
index e7fc1d6..7f056ad 100644
--- a/lib_vector_search/include/timer.h
+++ b/lib_vector_search/include/timer.h
@@ -1,6 +1,7 @@
 #pragma once
 
 #include <chrono>
+#include <ostream>
 
 class Timer {
 private: