diff --git a/lib_vector_search/src/word_list.cpp b/lib_vector_search/src/word_list.cpp
index e1baf7c..c4e4294 100644
--- a/lib_vector_search/src/word_list.cpp
+++ b/lib_vector_search/src/word_list.cpp
@@ -1,7 +1,9 @@
 #include "word_list.h"
 
 #include <algorithm>
+#include <cmath>
 #include <fstream>
+#include <initializer_list>
 #include <random>
 
 WordList &WordList::multiply(size_t factor) {
@@ -26,12 +28,12 @@ WordList &WordList::shuffle() {
 }
 
 WordList WordList::oneCap() {
-  const static std::string charset_ = "ABCDEFGHIJKLMNOPQRSTUVWXYZ";
+  const static std::string charset = "ABCDEFGHIJKLMNOPQRSTUVWXYZ";
 
   WordList word_list;
-  word_list.reserve(charset_.length());
+  word_list.reserve(charset.length());
 
-  for (auto char_1 : charset_) {
+  for (const auto char_1 : charset) {
     word_list.emplace_back(std::initializer_list<char>({char_1}));
   }
 
@@ -39,15 +41,15 @@ WordList WordList::oneCap() {
 };
 
 WordList WordList::fourCaps() {
-  const static std::string charset_ = "ABCDEFGHIJKLMNOPQRSTUVWXYZ";
+  const static std::string charset = "ABCDEFGHIJKLMNOPQRSTUVWXYZ";
 
   WordList word_list;
-  word_list.reserve(std::pow(charset_.length(), 4));
+  word_list.reserve(std::pow(charset.length(), 4));
 
-  for (auto char_1 : charset_) {
-    for (auto char_2 : charset_) {
-      for (auto char_3 : charset_) {
-        for (auto char_4 : charset_) {
+  for (const auto char_1 : charset) {
+    for (const auto char_2 : charset) {
+      for (const auto char_3 : charset) {
+        for (const auto char_4 : charset) {
           word_list.emplace_back(
               std::initializer_list<char>({char_1, char_2, char_3, char_4}));
         }