diff --git a/common.cpp b/common.cpp
index c126743..4dd1bb5 100644
--- a/common.cpp
+++ b/common.cpp
@@ -172,11 +172,11 @@ void show_nested_histogram(const pCaches& fcc, std::string Cache::*ptr, std::str
 			if (own.first.empty()) own.first = "[unknown]";
 			if (i < HIST_MAX) {
 				std::map<std::string, int> subhistogram;
-				std::vector<std::pair<std::string, int>> subpairs;
 				for (auto el : fcc)
 					if (el->*ptr == own.first && !(el->*ptr2).empty()) //TODO problem with [unknown]
 						subhistogram[el->*ptr2]++;
 				if (!subhistogram.empty()) {
+					std::vector<std::pair<std::string, int>> subpairs;
 					std::cout << "<details class=\"nested\"><summary class=\"bar\" style=\"--percent: " << 100 * own.second / max << "%;\"><span class=\"text\">" << own.first << ": " << own.second << "</span></summary>\n";
 					std::copy(subhistogram.begin(), subhistogram.end(), std::back_inserter(subpairs));
 					if (sort_by_val)
diff --git a/ocdb.cpp b/ocdb.cpp
index 2ea0aba..32c1d95 100644
--- a/ocdb.cpp
+++ b/ocdb.cpp
@@ -12,7 +12,7 @@ using json = nlohmann::json;
 // using namespace std::literals::string_literals;
 
 OCdb::OCdb(const Service service) {
-	int res = 0;
+	int res;
 
 	switch (service) {
 		case ocpl:
@@ -271,19 +271,19 @@ bool OCdb::update_log(const json& j) {
 		return 1;
 
 	sql = "INSERT INTO logs (uuid,";
-	for (auto& i : fields)
+	for (const auto& i : fields)
 		sql += i.first + ',';
-	for (auto& i : fields2)
+	for (const auto& i : fields2)
 		sql += i.first + ',';
 	sql.pop_back();
 	sql += ") VALUES ('" + uuid + "',";
-	for (__attribute__((unused)) auto& i : fields)
+	for (__attribute__((unused)) const auto& i : fields)
 		sql += "?,";
-	for (__attribute__((unused)) auto& i : fields2)
+	for (__attribute__((unused)) const auto& i : fields2)
 		sql += "?,";
 	sql.pop_back();
 	sql += ") ON CONFLICT(uuid) DO UPDATE SET ";
-	for (auto& i : fields)
+	for (const auto& i : fields)
 		sql += i.first + "=excluded." + i.first + ',';
 	sql.pop_back();
 	sql += ';';
@@ -295,10 +295,10 @@ bool OCdb::update_log(const json& j) {
 		return 0;
 	}
 	int n = 1;
-	for (auto& i : fields) {
+	for (const auto& i : fields) {
 		sqlite3_bind_text(stmt, n++, i.second.c_str(), -1, nullptr);
 	}
-	for (auto& i : fields2) {
+	for (const auto& i : fields2) {
 		sqlite3_bind_int(stmt, n++, i.second);
 	}
 	res = sqlite3_step(stmt);
diff --git a/okapi.cpp b/okapi.cpp
index e62e1ac..70ffa27 100644
--- a/okapi.cpp
+++ b/okapi.cpp
@@ -108,11 +108,11 @@ void Okapi::get_caches_json(const std::string& codes) const {
 	curl_post(api_service, query);
 }
 
-void Okapi::get_caches_ratings_json(const std::string& codes) const {
-	std::string api_service = url + OKAPI_caches;
-	std::string query = "consumer_key=" + key + "&cache_codes=" + codes + "&fields=code|recommendations|rating|status";
-	curl_post(api_service, query);
-}
+// void Okapi::get_caches_ratings_json(const std::string& codes) const {
+// 	std::string api_service = url + OKAPI_caches;
+// 	std::string query = "consumer_key=" + key + "&cache_codes=" + codes + "&fields=code|recommendations|rating|status";
+// 	curl_post(api_service, query);
+// }
 
 // Cache Okapi::get_cache(std::string code) {
 // 	std::string output = get_cache_json(code);
@@ -355,10 +355,10 @@ std::string Okapi::get_changelog_json(int revision) const {
 }
 
 void Okapi::get_ftf(uint uid, Caches& cc) const {
-	std::string url = "https://opencaching.pl/UserProfile/getUserFtfsAjax/" + std::to_string(uid);
+	std::string ftf_url = "https://opencaching.pl/UserProfile/getUserFtfsAjax/" + std::to_string(uid);
 	CURLcode res;
 
-	curl_easy_setopt(curl, CURLOPT_URL, url.c_str());
+	curl_easy_setopt(curl, CURLOPT_URL, ftf_url.c_str());
 	curl_easy_setopt(curl, CURLOPT_POSTFIELDS, "");
 	curl_output.clear();
 
diff --git a/okapi.h b/okapi.h
index 31b0af9..a559e71 100644
--- a/okapi.h
+++ b/okapi.h
@@ -23,7 +23,7 @@ private:
 	void get_user_caches_json(const std::string& uuid, int count = 0, int offset = 0) const;
 	// 	std::string get_cache_json(std::string code) const;
 	void get_caches_json(const std::string& codes) const;
-	void get_caches_ratings_json(const std::string& codes) const;
+	// void get_caches_ratings_json(const std::string& codes) const;
 
 	const static int MAX_LOGS = 1000;
 	const static int MAX_CACHES = 500;
@@ -43,7 +43,7 @@ private:
 	constexpr static auto ocuk_url = "https://opencache.uk/okapi/";
 
 public:
-	Okapi(const Service serv);
+	explicit Okapi(const Service serv);
 	~Okapi();
 
 	// 	Cache get_cache(std::string code);
diff --git a/powertrail.h b/powertrail.h
index f581d57..6596bd3 100644
--- a/powertrail.h
+++ b/powertrail.h
@@ -69,7 +69,7 @@ class Caches_in_Powertrails {
 public:
 	std::unordered_map<std::string, int> data;
 
-	Caches_in_Powertrails(const PowertrailDB& db);
+	explicit Caches_in_Powertrails(const PowertrailDB& db);
 	Caches_in_Powertrails(){};
 
 	void read_from_json(std::string file);
diff --git a/user.cpp b/user.cpp
index e8c86a6..a2fe75e 100644
--- a/user.cpp
+++ b/user.cpp
@@ -198,7 +198,7 @@ void User::prepare_lists_of_caches() {
 	}
 }
 
-void User::header() {
+void User::header() const {
 	if (!ocpl_user.empty())
 		std::cout << "<img alt=\"OCpl\" src=\"" << flag_pl << "\"> <a href=\"" << ocpl_user_profile << "\">" << ocpl_user << "</a><br>\n";
 	if (!ocde_user.empty())
diff --git a/user.h b/user.h
index e1fff10..8c4dbce 100644
--- a/user.h
+++ b/user.h
@@ -64,5 +64,5 @@ public:
 	void get_caches();
 	void prepare_lists_of_caches(); // Prepare sorted list of caches, excluding moving caches
 
-	void header();
+	void header() const;
 };