diff --git a/src/cheat_gui.cpp b/src/cheat_gui.cpp
index f2000856b8..00a73a5ca0 100644
--- a/src/cheat_gui.cpp
+++ b/src/cheat_gui.cpp
@@ -336,39 +336,38 @@ struct CheatWindow : Window {
 
 		uint width = 0;
 		uint lines = 0;
-		for (int i = 0; i != lengthof(_cheats_ui); i++) {
-			const CheatEntry *ce = &_cheats_ui[i];
-			if (!IsCheatAllowed(ce->mode)) continue;
+		for (const CheatEntry &ce : _cheats_ui) {
+			if (!IsCheatAllowed(ce.mode)) continue;
 			lines++;
-			switch (ce->type) {
+			switch (ce.type) {
 				case SLF_ALLOW_CONTROL:
 					/* Change inflation factors */
 					break;
 
 				case SLE_BOOL:
 					SetDParam(0, STR_CONFIG_SETTING_ON);
-					width = std::max(width, GetStringBoundingBox(ce->str).width);
+					width = std::max(width, GetStringBoundingBox(ce.str).width);
 					SetDParam(0, STR_CONFIG_SETTING_OFF);
-					width = std::max(width, GetStringBoundingBox(ce->str).width);
+					width = std::max(width, GetStringBoundingBox(ce.str).width);
 					break;
 
 				default:
-					switch (ce->str) {
+					switch (ce.str) {
 						/* Display date for change date cheat */
 						case STR_CHEAT_CHANGE_DATE:
 							SetDParam(0, CalTime::ConvertYMDToDate(CalTime::MAX_YEAR, 11, 31));
-							width = std::max(width, GetStringBoundingBox(ce->str).width);
+							width = std::max(width, GetStringBoundingBox(ce.str).width);
 							break;
 
 						/* Draw coloured flag for change company cheat */
 						case STR_CHEAT_CHANGE_COMPANY:
 							SetDParamMaxValue(0, MAX_COMPANIES);
-							width = std::max(width, GetStringBoundingBox(ce->str).width + WidgetDimensions::scaled.hsep_wide * 4);
+							width = std::max(width, GetStringBoundingBox(ce.str).width + WidgetDimensions::scaled.hsep_wide * 4);
 							break;
 
 						default:
 							SetDParam(0, INT64_MAX);
-							width = std::max(width, GetStringBoundingBox(ce->str).width);
+							width = std::max(width, GetStringBoundingBox(ce.str).width);
 							break;
 					}
 					break;
diff --git a/src/company_gui.cpp b/src/company_gui.cpp
index 12a6255931..51a079a518 100644
--- a/src/company_gui.cpp
+++ b/src/company_gui.cpp
@@ -2379,8 +2379,8 @@ struct CompanyWindow : Window
 
 			case WID_C_DESC_VEHICLE_COUNTS:
 				SetDParamMaxValue(0, 5000); // Maximum number of vehicles
-				for (uint i = 0; i < lengthof(_company_view_vehicle_count_strings); i++) {
-					size.width = std::max(size.width, GetStringBoundingBox(_company_view_vehicle_count_strings[i]).width + padding.width);
+				for (const auto &count_string : _company_view_vehicle_count_strings) {
+					size.width = std::max(size.width, GetStringBoundingBox(count_string).width + padding.width);
 				}
 				break;
 
diff --git a/src/fileio.cpp b/src/fileio.cpp
index 8d921033d0..746b5072b7 100644
--- a/src/fileio.cpp
+++ b/src/fileio.cpp
@@ -202,7 +202,7 @@ static FILE *FioFOpenFileSp(const std::string &filename, const char *mode, Searc
 	 * a string, but a variable, it 'renames' the variable,
 	 * so make that variable to makes it compile happily */
 	wchar_t Lmode[5];
-	MultiByteToWideChar(CP_ACP, 0, mode, -1, Lmode, lengthof(Lmode));
+	MultiByteToWideChar(CP_ACP, 0, mode, -1, Lmode, static_cast<int>(std::size(Lmode)));
 #endif
 	FILE *f = nullptr;
 	std::string buf;
diff --git a/src/fontcache/spritefontcache.cpp b/src/fontcache/spritefontcache.cpp
index 2baf223d2d..ca82b433f2 100644
--- a/src/fontcache/spritefontcache.cpp
+++ b/src/fontcache/spritefontcache.cpp
@@ -84,16 +84,16 @@ void SpriteFontCache::InitializeUnicodeGlyphMap()
 		this->SetUnicodeGlyph(i + SCC_SPRITE_START, sprite);
 	}
 
-	for (uint i = 0; i < lengthof(_default_unicode_map); i++) {
-		uint8_t key = _default_unicode_map[i].key;
+	for (const auto &unicode_map : _default_unicode_map) {
+		uint8_t key = unicode_map.key;
 		if (key == CLRA) {
 			/* Clear the glyph. This happens if the glyph at this code point
 			 * is non-standard and should be accessed by an SCC_xxx enum
 			 * entry only. */
-			this->SetUnicodeGlyph(_default_unicode_map[i].code, 0);
+			this->SetUnicodeGlyph(unicode_map.code, 0);
 		} else {
 			SpriteID sprite = base + key - ASCII_LETTERSTART;
-			this->SetUnicodeGlyph(_default_unicode_map[i].code, sprite);
+			this->SetUnicodeGlyph(unicode_map.code, sprite);
 		}
 	}
 	font_height_cache[this->fs] = this->GetHeight();
diff --git a/src/group_gui.cpp b/src/group_gui.cpp
index 71435048a3..195e0233fa 100644
--- a/src/group_gui.cpp
+++ b/src/group_gui.cpp
@@ -291,8 +291,8 @@ private:
 		this->column_size[VGC_PROFIT].width = 0;
 		this->column_size[VGC_PROFIT].height = 0;
 		static const SpriteID profit_sprites[] = {SPR_PROFIT_NA, SPR_PROFIT_NEGATIVE, SPR_PROFIT_SOME, SPR_PROFIT_LOT};
-		for (uint i = 0; i < lengthof(profit_sprites); i++) {
-			Dimension d = GetSpriteSize(profit_sprites[i]);
+		for (const auto &profit_sprite : profit_sprites) {
+			Dimension d = GetSpriteSize(profit_sprite);
 			this->column_size[VGC_PROFIT] = maxdim(this->column_size[VGC_PROFIT], d);
 		}
 		this->tiny_step_height = std::max(this->tiny_step_height, this->column_size[VGC_PROFIT].height);
diff --git a/src/industry_gui.cpp b/src/industry_gui.cpp
index bccfa81f7e..2353fc1955 100644
--- a/src/industry_gui.cpp
+++ b/src/industry_gui.cpp
@@ -830,13 +830,7 @@ static void UpdateIndustryProduction(Industry *i);
 static inline bool IsProductionAlterable(const Industry *i)
 {
 	const IndustrySpec *is = GetIndustrySpec(i->type);
-	bool has_prod = false;
-	for (size_t j = 0; j < std::size(is->production_rate); j++) {
-		if (is->production_rate[j] != 0) {
-			has_prod = true;
-			break;
-		}
-	}
+	bool has_prod = std::any_of(std::begin(is->production_rate), std::end(is->production_rate), [](auto rate) { return rate != 0; });
 	return ((_game_mode == GM_EDITOR || _cheats.setup_prod.value) &&
 			(has_prod || is->IsRawIndustry()) &&
 			!_networking);
diff --git a/src/lang/brazilian_portuguese.txt b/src/lang/brazilian_portuguese.txt
index 548f4c9894..336d63c4e9 100644
--- a/src/lang/brazilian_portuguese.txt
+++ b/src/lang/brazilian_portuguese.txt
@@ -188,7 +188,7 @@ STR_COLOUR_ORANGE                                               :Laranja
 STR_COLOUR_BROWN                                                :Marrom
 STR_COLOUR_GREY                                                 :Cinza
 STR_COLOUR_WHITE                                                :Branco
-STR_COLOUR_RANDOM                                               :Aleatório
+STR_COLOUR_RANDOM                                               :Aleatória
 
 ###length 17
 STR_COLOUR_SECONDARY_DARK_BLUE                                  :Azul Escuro
diff --git a/src/lang/polish.txt b/src/lang/polish.txt
index 89b03df67f..3a0a8fd9fe 100644
--- a/src/lang/polish.txt
+++ b/src/lang/polish.txt
@@ -3921,7 +3921,7 @@ STR_NEWGRF_ERROR_MULTIPLE_ACTION_8                              :Zawiera wiele w
 STR_NEWGRF_ERROR_READ_BOUNDS                                    :Odczyt poza obszar pseudo-sprite'u (sprite {3:NUM})
 STR_NEWGRF_ERROR_GRM_FAILED                                     :Potrzebne źródło GRF nie jest dostępne (sprite {3:NUM})
 STR_NEWGRF_ERROR_FORCEFULLY_DISABLED                            :{1:STRING} został wyłączony przez {STRING}
-STR_NEWGRF_ERROR_INVALID_SPRITE_LAYOUT                          :Niepoprawny/nieznany format układu sprite'u (sprite {3:NUM})
+STR_NEWGRF_ERROR_INVALID_SPRITE_LAYOUT                          :Nieprawidłowy/nieznany format układu sprite'a (sprite {3:NUM})
 STR_NEWGRF_ERROR_LIST_PROPERTY_TOO_LONG                         :Zbyt wiele elementów na liście wartości właściwości (sprite {3:NUM}, właściwość {4:HEX})
 STR_NEWGRF_ERROR_INDPROD_CALLBACK                               :Nieprawidłowe wywołanie zwrotne produkcji przedsiębiorstwa (sprite {3:NUM}, „{2:STRING}”)
 
diff --git a/src/linkgraph/linkgraphschedule.cpp b/src/linkgraph/linkgraphschedule.cpp
index bf8ad1aa12..118b0cbb26 100644
--- a/src/linkgraph/linkgraphschedule.cpp
+++ b/src/linkgraph/linkgraphschedule.cpp
@@ -152,9 +152,9 @@ void LinkGraphSchedule::JoinNext()
  */
 /* static */ void LinkGraphSchedule::Run(LinkGraphJob *job)
 {
-	for (uint i = 0; i < lengthof(instance.handlers); ++i) {
+	for (const auto &handler : instance.handlers) {
 		if (job->IsJobAborted()) return;
-		instance.handlers[i]->Run(*job);
+		handler->Run(*job);
 	}
 
 	/*
diff --git a/src/misc/getoptdata.cpp b/src/misc/getoptdata.cpp
index df54391232..fbc4907375 100644
--- a/src/misc/getoptdata.cpp
+++ b/src/misc/getoptdata.cpp
@@ -21,23 +21,20 @@
  */
 int GetOptData::GetOpt()
 {
-	const OptionData *odata;
-
-	char *s = this->cont;
+	const char *s = this->cont;
 	if (s == nullptr) {
-		if (this->numleft == 0) return -1; // No arguments left -> finished.
+		if (this->arguments.empty()) return -1; // No arguments left -> finished.
 
-		s = this->argv[0];
+		s = this->arguments[0];
 		if (*s != '-') return -1; // No leading '-' -> not an option -> finished.
 
-		this->argv++;
-		this->numleft--;
+		this->arguments = this->arguments.subspan(1);
 
 		/* Is it a long option? */
-		for (odata = this->options; odata->flags != ODF_END; odata++) {
-			if (odata->longname != nullptr && !strcmp(odata->longname, s)) { // Long options always use the entire argument.
+		for (auto &option : this->options) {
+			if (option.longname != nullptr && !strcmp(option.longname, s)) { // Long options always use the entire argument.
 				this->cont = nullptr;
-				goto set_optval;
+				return this->GetOpt(option);
 			}
 		}
 
@@ -45,39 +42,41 @@ int GetOptData::GetOpt()
 	}
 
 	/* Is it a short option? */
-	for (odata = this->options; odata->flags != ODF_END; odata++) {
-		if (odata->shortname != '\0' && *s == odata->shortname) {
+	for (auto &option : this->options) {
+		if (option.shortname != '\0' && *s == option.shortname) {
 			this->cont = (s[1] != '\0') ? s + 1 : nullptr;
-
-set_optval: // Handle option value of *odata .
-			this->opt = nullptr;
-			switch (odata->flags) {
-				case ODF_NO_VALUE:
-					return odata->id;
-
-				case ODF_HAS_VALUE:
-				case ODF_OPTIONAL_VALUE:
-					if (this->cont != nullptr) { // Remainder of the argument is the option value.
-						this->opt = this->cont;
-						this->cont = nullptr;
-						return odata->id;
-					}
-					/* No more arguments, either return an error or a value-less option. */
-					if (this->numleft == 0) return (odata->flags == ODF_HAS_VALUE) ? -2 : odata->id;
-
-					/* Next argument looks like another option, let's not return it as option value. */
-					if (odata->flags == ODF_OPTIONAL_VALUE && this->argv[0][0] == '-') return odata->id;
-
-					this->opt = this->argv[0]; // Next argument is the option value.
-					this->argv++;
-					this->numleft--;
-					return odata->id;
-
-				default: NOT_REACHED();
-			}
+			return this->GetOpt(option);
 		}
 	}
 
 	return -2; // No other ways to interpret the text -> error.
 }
 
+int GetOptData::GetOpt(const OptionData &option)
+{
+	this->opt = nullptr;
+	switch (option.type) {
+		case ODF_NO_VALUE:
+			return option.id;
+
+		case ODF_HAS_VALUE:
+		case ODF_OPTIONAL_VALUE:
+			if (this->cont != nullptr) { // Remainder of the argument is the option value.
+				this->opt = this->cont;
+				this->cont = nullptr;
+				return option.id;
+			}
+			/* No more arguments, either return an error or a value-less option. */
+			if (this->arguments.empty()) return (option.type == ODF_HAS_VALUE) ? -2 : option.id;
+
+			/* Next argument looks like another option, let's not return it as option value. */
+			if (option.type == ODF_OPTIONAL_VALUE && this->arguments[0][0] == '-') return option.id;
+
+			this->opt = this->arguments[0]; // Next argument is the option value.
+			this->arguments = this->arguments.subspan(1);
+			return option.id;
+
+		default: NOT_REACHED();
+	}
+}
+
diff --git a/src/misc/getoptdata.h b/src/misc/getoptdata.h
index b62d20c2db..bdff5a877f 100644
--- a/src/misc/getoptdata.h
+++ b/src/misc/getoptdata.h
@@ -11,100 +11,39 @@
 #define GETOPTDATA_H
 
 /** Flags of an option. */
-enum OptionDataFlags {
+enum OptionDataType : uint8_t {
 	ODF_NO_VALUE,       ///< A plain option (no value attached to it).
 	ODF_HAS_VALUE,      ///< An option with a value.
 	ODF_OPTIONAL_VALUE, ///< An option with an optional value.
-	ODF_END,            ///< Terminator (data is not parsed further).
 };
 
 /** Data of an option. */
 struct OptionData {
-	uint8_t id;           ///< Unique identification of this option data, often the same as #shortname.
-	char shortname;       ///< Short option letter if available, else use \c '\0'.
-	uint16_t flags;       ///< Option data flags. @see OptionDataFlags
-	const char *longname; ///< Long option name including '-'/'--' prefix, use \c nullptr if not available.
+	OptionDataType type;            ///< The type of option.
+	char id;                        ///< Unique identification of this option data, often the same as #shortname.
+	char shortname = '\0';          ///< Short option letter if available, else use \c '\0'.
+	const char *longname = nullptr; ///< Long option name including '-'/'--' prefix, use \c nullptr if not available.
 };
 
 /** Data storage for parsing command line options. */
 struct GetOptData {
-	char *opt;                 ///< Option value, if available (else \c nullptr).
-	int numleft;               ///< Number of arguments left in #argv.
-	char **argv;               ///< Remaining command line arguments.
-	const OptionData *options; ///< Command line option descriptions.
-	char *cont;                ///< Next call to #GetOpt should start here (in the middle of an argument).
+	using OptionSpan = std::span<const OptionData>;
+	using ArgumentSpan = std::span<char * const>;
+
+	ArgumentSpan arguments; ///< Remaining command line arguments.
+	const OptionSpan options; ///< Command line option descriptions.
+	const char *opt = nullptr; ///< Option value, if available (else \c nullptr).
+	const char *cont = nullptr; ///< Next call to #GetOpt should start here (in the middle of an argument).
 
 	/**
 	 * Constructor of the data store.
-	 * @param argc Number of command line arguments, excluding the program name.
-	 * @param argv Command line arguments, excluding the program name.
+	 * @param argument The command line arguments, excluding the program name.
 	 * @param options Command line option descriptions.
 	 */
-	GetOptData(int argc, char **argv, const OptionData *options) :
-			opt(nullptr),
-			numleft(argc),
-			argv(argv),
-			options(options),
-			cont(nullptr)
-	{
-	}
+	GetOptData(ArgumentSpan arguments, OptionSpan options) : arguments(arguments), options(options) {}
 
 	int GetOpt();
+	int GetOpt(const OptionData &option);
 };
 
-/**
- * General macro for creating an option.
- * @param id        Identification of the option.
- * @param shortname Short option name. Use \c '\0' if not used.
- * @param longname  Long option name including leading '-' or '--'. Use \c nullptr if not used.
- * @param flags     Flags of the option.
- */
-#define GETOPT_GENERAL(id, shortname, longname, flags) { id, shortname, flags, longname }
-
-/**
- * Short option without value.
- * @param shortname Short option name. Use \c '\0' if not used.
- * @param longname  Long option name including leading '-' or '--'. Use \c nullptr if not used.
- */
-#define GETOPT_NOVAL(shortname, longname) GETOPT_GENERAL(shortname, shortname, longname, ODF_NO_VALUE)
-
-/**
- * Short option with value.
- * @param shortname Short option name. Use \c '\0' if not used.
- * @param longname  Long option name including leading '-' or '--'. Use \c nullptr if not used.
- */
-#define GETOPT_VALUE(shortname, longname) GETOPT_GENERAL(shortname, shortname, longname, ODF_HAS_VALUE)
-
-/**
- * Short option with optional value.
- * @param shortname Short option name. Use \c '\0' if not used.
- * @param longname  Long option name including leading '-' or '--'. Use \c nullptr if not used.
- * @note Options with optional values are hopelessly ambiguous, eg "-opt -value", avoid them.
- */
-#define GETOPT_OPTVAL(shortname, longname) GETOPT_GENERAL(shortname, shortname, longname, ODF_OPTIONAL_VALUE)
-
-
-/**
- * Short option without value.
- * @param shortname Short option name. Use \c '\0' if not used.
- */
-#define GETOPT_SHORT_NOVAL(shortname) GETOPT_NOVAL(shortname, nullptr)
-
-/**
- * Short option with value.
- * @param shortname Short option name. Use \c '\0' if not used.
- */
-#define GETOPT_SHORT_VALUE(shortname) GETOPT_VALUE(shortname, nullptr)
-
-/**
- * Short option with optional value.
- * @param shortname Short option name. Use \c '\0' if not used.
- * @note Options with optional values are hopelessly ambiguous, eg "-opt -value", avoid them.
- */
-#define GETOPT_SHORT_OPTVAL(shortname) GETOPT_OPTVAL(shortname, nullptr)
-
-/** Option terminator. */
-#define GETOPT_END() { '\0', '\0', ODF_END, nullptr}
-
-
 #endif /* GETOPTDATA_H */
diff --git a/src/music/dmusic.cpp b/src/music/dmusic.cpp
index 2146542859..c0f0b16a56 100644
--- a/src/music/dmusic.cpp
+++ b/src/music/dmusic.cpp
@@ -885,7 +885,7 @@ static const char *LoadDefaultDLSFile(const char *user_dls)
 				DWORD buf_size = sizeof(dls_path); // Buffer size as to be given in bytes!
 				if (SUCCEEDED(RegQueryValueEx(hkDM, L"GMFilePath", nullptr, nullptr, (LPBYTE)dls_path, &buf_size))) {
 					wchar_t expand_path[MAX_PATH * 2];
-					ExpandEnvironmentStrings(dls_path, expand_path, lengthof(expand_path));
+					ExpandEnvironmentStrings(dls_path, expand_path, static_cast<DWORD>(std::size(expand_path)));
 					if (!dls_file.LoadFile(expand_path)) DEBUG(driver, 1, "Failed to load default GM DLS file from registry");
 				}
 				RegCloseKey(hkDM);
@@ -895,7 +895,7 @@ static const char *LoadDefaultDLSFile(const char *user_dls)
 			if (dls_file.instruments.empty()) {
 				static const wchar_t *DLS_GM_FILE = L"%windir%\\System32\\drivers\\gm.dls";
 				wchar_t path[MAX_PATH];
-				ExpandEnvironmentStrings(DLS_GM_FILE, path, lengthof(path));
+				ExpandEnvironmentStrings(DLS_GM_FILE, path, static_cast<DWORD>(std::size(path)));
 
 				if (!dls_file.LoadFile(path)) return "Can't load GM DLS collection";
 			}
diff --git a/src/music_gui.cpp b/src/music_gui.cpp
index ea2d2a3fe3..741347ab8a 100644
--- a/src/music_gui.cpp
+++ b/src/music_gui.cpp
@@ -107,7 +107,7 @@ void MusicSystem::BuildPlaylists()
 	const MusicSet *set = BaseMusic::GetUsedSet();
 
 	/* Clear current playlists */
-	for (size_t i = 0; i < lengthof(this->standard_playlists); ++i) this->standard_playlists[i].clear();
+	for (auto &playlist : this->standard_playlists) playlist.clear();
 	this->music_set.clear();
 
 	/* Build standard playlists, and a list of available music */
diff --git a/src/network/core/http_winhttp.cpp b/src/network/core/http_winhttp.cpp
index 04ddaad08a..ea29fb5fa4 100644
--- a/src/network/core/http_winhttp.cpp
+++ b/src/network/core/http_winhttp.cpp
@@ -78,7 +78,7 @@ static std::string GetLastErrorAsString()
 	DWORD error_code = GetLastError();
 
 	if (FormatMessage(FORMAT_MESSAGE_FROM_SYSTEM | FORMAT_MESSAGE_FROM_HMODULE | FORMAT_MESSAGE_IGNORE_INSERTS, GetModuleHandle(L"winhttp.dll"), error_code,
-		MAKELANGID(LANG_NEUTRAL, SUBLANG_DEFAULT), buffer, lengthof(buffer), nullptr) == 0) {
+		MAKELANGID(LANG_NEUTRAL, SUBLANG_DEFAULT), buffer, static_cast<DWORD>(std::size(buffer)), nullptr) == 0) {
 		return fmt::format("unknown error {}", error_code);
 	}
 
@@ -222,11 +222,11 @@ void NetworkHTTPRequest::Connect()
 	/* Convert the URL to its components. */
 	url_components.dwStructSize = sizeof(url_components);
 	url_components.lpszScheme = scheme;
-	url_components.dwSchemeLength = lengthof(scheme);
+	url_components.dwSchemeLength = static_cast<DWORD>(std::size(scheme));
 	url_components.lpszHostName = hostname;
-	url_components.dwHostNameLength = lengthof(hostname);
+	url_components.dwHostNameLength = static_cast<DWORD>(std::size(hostname));
 	url_components.lpszUrlPath = url_path;
-	url_components.dwUrlPathLength = lengthof(url_path);
+	url_components.dwUrlPathLength = static_cast<DWORD>(std::size(url_path));
 	WinHttpCrackUrl(this->uri.c_str(), 0, 0, &url_components);
 
 	/* Create the HTTP connection. */
diff --git a/src/network/core/os_abstraction.cpp b/src/network/core/os_abstraction.cpp
index 8d3349392f..a461b436cc 100644
--- a/src/network/core/os_abstraction.cpp
+++ b/src/network/core/os_abstraction.cpp
@@ -82,7 +82,7 @@ const char *NetworkError::AsString() const
 #if defined(_WIN32)
 		wchar_t buffer[512];
 		if (FormatMessage(FORMAT_MESSAGE_FROM_SYSTEM | FORMAT_MESSAGE_IGNORE_INSERTS, nullptr, this->error,
-			MAKELANGID(LANG_NEUTRAL, SUBLANG_DEFAULT), buffer, lengthof(buffer), nullptr) == 0) {
+			MAKELANGID(LANG_NEUTRAL, SUBLANG_DEFAULT), buffer, static_cast<DWORD>(std::size(buffer)), nullptr) == 0) {
 			char errbuffer[32];
 			seprintf(errbuffer, lastof(errbuffer), "Unknown error %d", this->error);
 			this->message.assign(errbuffer);
diff --git a/src/newgrf_engine.cpp b/src/newgrf_engine.cpp
index b0c997a729..5539850175 100644
--- a/src/newgrf_engine.cpp
+++ b/src/newgrf_engine.cpp
@@ -1591,11 +1591,11 @@ void FillNewGRFVehicleCache(const Vehicle *v)
 	static_assert(NCVV_END == lengthof(cache_entries) + lengthof(partial_cache_entries));
 
 	/* Resolve all the variables, so their caches are set. */
-	for (size_t i = 0; i < lengthof(cache_entries); i++) {
+	for (const auto &cache_entry : cache_entries) {
 		/* Only resolve when the cache isn't valid. */
-		if (HasBit(v->grf_cache.cache_valid, cache_entries[i][1])) continue;
+		if (HasBit(v->grf_cache.cache_valid, cache_entry[1])) continue;
 		GetVariableExtra extra;
-		ro.GetScope(VSG_SCOPE_SELF)->GetVariable(cache_entries[i][0], 0, &extra);
+		ro.GetScope(VSG_SCOPE_SELF)->GetVariable(cache_entry[0], 0, &extra);
 	}
 
 	/* Make sure really all bits are set. */
diff --git a/src/newgrf_generic.cpp b/src/newgrf_generic.cpp
index 4fe50d0b67..e38a733e2f 100644
--- a/src/newgrf_generic.cpp
+++ b/src/newgrf_generic.cpp
@@ -98,8 +98,8 @@ static GenericCallbackList _gcl[GSF_END];
  */
 void ResetGenericCallbacks()
 {
-	for (uint8_t feature = 0; feature < lengthof(_gcl); feature++) {
-		_gcl[feature].clear();
+	for (auto &gcl : _gcl) {
+		gcl.clear();
 	}
 }
 
diff --git a/src/openttd.cpp b/src/openttd.cpp
index 166409e10a..efb41a5a64 100644
--- a/src/openttd.cpp
+++ b/src/openttd.cpp
@@ -728,39 +728,31 @@ void PostMainLoop()
 extern void DedicatedFork();
 #endif
 
-/** Options of OpenTTD. */
-static const OptionData _options[] = {
-	 GETOPT_SHORT_VALUE('I'),
-	 GETOPT_SHORT_VALUE('S'),
-	 GETOPT_SHORT_VALUE('M'),
-	 GETOPT_SHORT_VALUE('m'),
-	 GETOPT_SHORT_VALUE('s'),
-	 GETOPT_SHORT_VALUE('v'),
-	 GETOPT_SHORT_VALUE('b'),
-	GETOPT_SHORT_OPTVAL('D'),
-	 GETOPT_SHORT_VALUE('n'),
-	 GETOPT_SHORT_VALUE('p'),
-	 GETOPT_SHORT_VALUE('P'),
+/**
+ * Create all the options that OpenTTD supports. Each option is
+ * always a single character with no, an optional or a required value.
+ * @return The available options.
+ */
+static std::vector<OptionData> CreateOptions()
+{
+	std::vector<OptionData> options;
+	/* Options that require a parameter. */
+	for (char c : "GIMPSbcmnpqrstv") options.push_back({ .type = ODF_HAS_VALUE, .id = c, .shortname = c });
 #if !defined(_WIN32)
-	 GETOPT_SHORT_NOVAL('f'),
+	options.push_back({ .type = ODF_HAS_VALUE, .id = 'f', .shortname = 'f' });
 #endif
-	 GETOPT_SHORT_VALUE('r'),
-	 GETOPT_SHORT_VALUE('t'),
-	GETOPT_SHORT_OPTVAL('d'),
-	 GETOPT_SHORT_NOVAL('e'),
-	GETOPT_SHORT_OPTVAL('g'),
-	 GETOPT_SHORT_VALUE('G'),
-	 GETOPT_SHORT_VALUE('c'),
-	 GETOPT_SHORT_NOVAL('x'),
-	 GETOPT_SHORT_NOVAL('X'),
-	 GETOPT_SHORT_VALUE('q'),
-	 GETOPT_SHORT_VALUE('K'),
-	 GETOPT_SHORT_NOVAL('h'),
-	 GETOPT_SHORT_NOVAL('Q'),
-	 GETOPT_SHORT_VALUE('J'),
-	 GETOPT_SHORT_NOVAL('Z'),
-	GETOPT_END()
-};
+
+	/* Options with an optional parameter. */
+	for (char c : "Ddg") options.push_back({ .type = ODF_OPTIONAL_VALUE, .id = c, .shortname = c });
+
+	/* Options without a parameter. */
+	for (char c : "QXehx") options.push_back({ .type = ODF_NO_VALUE, .id = c, .shortname = c });
+
+	/* Non-upstream options */
+	for (char c : "KJZ") options.push_back({ .type = ODF_HAS_VALUE, .id = c, .shortname = c });
+
+	return options;
+}
 
 /**
  * Main entry point for this lovely game.
@@ -795,7 +787,8 @@ int openttd_main(int argc, char *argv[])
 	_game_mode = GM_MENU;
 	_switch_mode = SM_MENU;
 
-	GetOptData mgo(argc - 1, argv + 1, _options);
+	auto options = CreateOptions();
+	GetOptData mgo(std::span(argv + 1, argc - 1), options);
 	int ret = 0;
 
 	int i;
@@ -942,7 +935,7 @@ int openttd_main(int argc, char *argv[])
 		if (i == -2) break;
 	}
 
-	if (i == -2 || mgo.numleft > 0) {
+	if (i == -2 || !mgo.arguments.empty()) {
 		/* Either the user typed '-h', they made an error, or they added unrecognized command line arguments.
 		 * In all cases, print the help, and exit.
 		 *
diff --git a/src/order_gui.cpp b/src/order_gui.cpp
index c98971e743..6fd9c3ed1f 100644
--- a/src/order_gui.cpp
+++ b/src/order_gui.cpp
@@ -1988,11 +1988,11 @@ public:
 
 			case WID_O_COND_VARIABLE: {
 				Dimension d = {0, 0};
-				for (uint i = 0; i < lengthof(_order_conditional_variable); i++) {
-					if (this->vehicle->type != VEH_TRAIN && _order_conditional_variable[i] == OCV_FREE_PLATFORMS) {
+				for (const auto &ocv : _order_conditional_variable) {
+					if (this->vehicle->type != VEH_TRAIN && ocv == OCV_FREE_PLATFORMS) {
 						continue;
 					}
-					d = maxdim(d, GetStringBoundingBox(OrderStringForVariable(this->vehicle, _order_conditional_variable[i])));
+					d = maxdim(d, GetStringBoundingBox(OrderStringForVariable(this->vehicle, ocv)));
 				}
 				d.width += padding.width;
 				d.height += padding.height;
@@ -3135,23 +3135,23 @@ public:
 				break;
 
 			case WID_O_COND_VARIABLE: {
-				const OrderConditionVariable ocv = this->vehicle->GetOrder(this->OrderGetSel())->GetConditionVariable();
+				const OrderConditionVariable current_ocv = this->vehicle->GetOrder(this->OrderGetSel())->GetConditionVariable();
 				DropDownList list;
-				for (uint i = 0; i < lengthof(_order_conditional_variable); i++) {
-					if (this->vehicle->type != VEH_TRAIN && _order_conditional_variable[i] == OCV_FREE_PLATFORMS) {
+				for (const auto &ocv : _order_conditional_variable) {
+					if (this->vehicle->type != VEH_TRAIN && ocv == OCV_FREE_PLATFORMS) {
 						continue;
 					}
-					if (ocv != _order_conditional_variable[i]) {
-						if (_order_conditional_variable[i] == OCV_COUNTER_VALUE && !_settings_client.gui.show_adv_tracerestrict_features) {
+					if (current_ocv != ocv) {
+						if (ocv == OCV_COUNTER_VALUE && !_settings_client.gui.show_adv_tracerestrict_features) {
 							continue;
 						}
-						if ((_order_conditional_variable[i] == OCV_DISPATCH_SLOT) && this->vehicle->orders->GetScheduledDispatchScheduleCount() == 0) {
+						if ((ocv == OCV_DISPATCH_SLOT) && this->vehicle->orders->GetScheduledDispatchScheduleCount() == 0) {
 							continue;
 						}
 					}
-					list.push_back(MakeDropDownListStringItem(OrderStringForVariable(this->vehicle, _order_conditional_variable[i]), _order_conditional_variable[i], false));
+					list.push_back(MakeDropDownListStringItem(OrderStringForVariable(this->vehicle, ocv), ocv, false));
 				}
-				ShowDropDownList(this, std::move(list), ocv, WID_O_COND_VARIABLE);
+				ShowDropDownList(this, std::move(list), current_ocv, WID_O_COND_VARIABLE);
 				break;
 			}
 
diff --git a/src/os/windows/library_loader_win.cpp b/src/os/windows/library_loader_win.cpp
index feb90b0629..42b8c93786 100644
--- a/src/os/windows/library_loader_win.cpp
+++ b/src/os/windows/library_loader_win.cpp
@@ -22,7 +22,7 @@ static std::string GetLoadError()
 
 	wchar_t buffer[512];
 	if (FormatMessage(FORMAT_MESSAGE_FROM_SYSTEM | FORMAT_MESSAGE_IGNORE_INSERTS, nullptr, error_code,
-		MAKELANGID(LANG_NEUTRAL, SUBLANG_DEFAULT), buffer, lengthof(buffer), nullptr) == 0) {
+		MAKELANGID(LANG_NEUTRAL, SUBLANG_DEFAULT), buffer, static_cast<DWORD>(std::size(buffer)), nullptr) == 0) {
 		return fmt::format("Unknown error {}", error_code);
 	}
 
diff --git a/src/os/windows/win32.cpp b/src/os/windows/win32.cpp
index 5c85b22848..986d1fd0a1 100644
--- a/src/os/windows/win32.cpp
+++ b/src/os/windows/win32.cpp
@@ -199,7 +199,7 @@ void FiosGetDrives(FileList &file_list)
 	wchar_t drives[256];
 	const wchar_t *s;
 
-	GetLogicalDriveStrings(lengthof(drives), drives);
+	GetLogicalDriveStrings(static_cast<DWORD>(std::size(drives)), drives);
 	for (s = drives; *s != '\0';) {
 		FiosItem *fios = &file_list.emplace_back();
 		fios->type = FIOS_TYPE_DRIVE;
@@ -419,7 +419,7 @@ void DetermineBasePaths(const char *exe)
 		/* Use the folder of the config file as working directory. */
 		wchar_t config_dir[MAX_PATH];
 		wcsncpy(path, convert_to_fs(_config_file, path, lengthof(path)), lengthof(path));
-		if (!GetFullPathName(path, lengthof(config_dir), config_dir, nullptr)) {
+		if (!GetFullPathName(path, static_cast<DWORD>(std::size(config_dir)), config_dir, nullptr)) {
 			DEBUG(misc, 0, "GetFullPathName failed (%lu)\n", GetLastError());
 			_searchpaths[SP_WORKING_DIR].clear();
 		} else {
@@ -431,13 +431,13 @@ void DetermineBasePaths(const char *exe)
 		}
 	}
 
-	if (!GetModuleFileName(nullptr, path, lengthof(path))) {
+	if (!GetModuleFileName(nullptr, path, static_cast<DWORD>(std::size(path)))) {
 		DEBUG(misc, 0, "GetModuleFileName failed (%lu)\n", GetLastError());
 		_searchpaths[SP_BINARY_DIR].clear();
 	} else {
 		wchar_t exec_dir[MAX_PATH];
-		wcsncpy(path, convert_to_fs(exe, path, lengthof(path)), lengthof(path));
-		if (!GetFullPathName(path, lengthof(exec_dir), exec_dir, nullptr)) {
+		wcsncpy(path, convert_to_fs(exe, path, std::size(path)), lengthof(path));
+		if (!GetFullPathName(path, static_cast<DWORD>(std::size(exec_dir)), exec_dir, nullptr)) {
 			DEBUG(misc, 0, "GetFullPathName failed (%lu)\n", GetLastError());
 			_searchpaths[SP_BINARY_DIR].clear();
 		} else {
@@ -551,8 +551,8 @@ const char *GetCurrentLocale(const char *)
 	const LCID userUiLocale = MAKELCID(userUiLang, SORT_DEFAULT);
 
 	char lang[9], country[9];
-	if (GetLocaleInfoA(userUiLocale, LOCALE_SISO639LANGNAME, lang, lengthof(lang)) == 0 ||
-	    GetLocaleInfoA(userUiLocale, LOCALE_SISO3166CTRYNAME, country, lengthof(country)) == 0) {
+	if (GetLocaleInfoA(userUiLocale, LOCALE_SISO639LANGNAME, lang, static_cast<int>(std::size(lang))) == 0 ||
+	    GetLocaleInfoA(userUiLocale, LOCALE_SISO3166CTRYNAME, country, static_cast<int>(std::size(country))) == 0) {
 		/* Unable to retrieve the locale. */
 		return nullptr;
 	}
@@ -578,7 +578,7 @@ void Win32SetCurrentLocaleName(std::string iso_code)
 		}
 	}
 
-	MultiByteToWideChar(CP_UTF8, 0, iso_code.c_str(), -1, _cur_iso_locale, lengthof(_cur_iso_locale));
+	MultiByteToWideChar(CP_UTF8, 0, iso_code.c_str(), -1, _cur_iso_locale, static_cast<int>(std::size(_cur_iso_locale)));
 }
 
 int OTTDStringCompare(std::string_view s1, std::string_view s2)
diff --git a/src/saveload/afterload.cpp b/src/saveload/afterload.cpp
index 1ec2a22a00..d3e432e9d4 100644
--- a/src/saveload/afterload.cpp
+++ b/src/saveload/afterload.cpp
@@ -2841,7 +2841,7 @@ bool AfterLoadGame()
 			uint8_t old_start;
 			uint8_t num_frames;
 		};
-		static const AirportTileConversion atc[] = {
+		static const AirportTileConversion atcs[] = {
 			{31,  12}, // APT_RADAR_GRASS_FENCE_SW
 			{50,   4}, // APT_GRASS_FENCE_NE_FLAG
 			{62,   2}, // 1 unused tile
@@ -2856,17 +2856,17 @@ bool AfterLoadGame()
 			if (IsAirportTile(t)) {
 				StationGfx old_gfx = GetStationGfx(t);
 				uint8_t offset = 0;
-				for (uint i = 0; i < lengthof(atc); i++) {
-					if (old_gfx < atc[i].old_start) {
+				for (const auto &atc : atcs) {
+					if (old_gfx < atc.old_start) {
 						SetStationGfx(t, old_gfx - offset);
 						break;
 					}
-					if (old_gfx < atc[i].old_start + atc[i].num_frames) {
-						SetAnimationFrame(t, old_gfx - atc[i].old_start);
-						SetStationGfx(t, atc[i].old_start - offset);
+					if (old_gfx < atc.old_start + atc.num_frames) {
+						SetAnimationFrame(t, old_gfx - atc.old_start);
+						SetStationGfx(t, atc.old_start - offset);
 						break;
 					}
-					offset += atc[i].num_frames - 1;
+					offset += atc.num_frames - 1;
 				}
 			}
 		}
diff --git a/src/script/script_info.cpp b/src/script/script_info.cpp
index 3eca3f4fa6..69cdff7480 100644
--- a/src/script/script_info.cpp
+++ b/src/script/script_info.cpp
@@ -47,8 +47,8 @@ bool ScriptInfo::CheckMethod(const char *name) const
 		"GetDate",
 		"CreateInstance",
 	};
-	for (size_t i = 0; i < lengthof(required_functions); i++) {
-		if (!info->CheckMethod(required_functions[i])) return SQ_ERROR;
+	for (const auto &required_function : required_functions) {
+		if (!info->CheckMethod(required_function)) return SQ_ERROR;
 	}
 
 	/* Get location information of the scanner */
diff --git a/src/settings_gui.cpp b/src/settings_gui.cpp
index 802038c791..957a904c0b 100644
--- a/src/settings_gui.cpp
+++ b/src/settings_gui.cpp
@@ -2863,8 +2863,8 @@ struct GameSettingsWindow : Window {
 					STR_CONFIG_SETTING_TYPE_COMPANY_MENU, STR_CONFIG_SETTING_TYPE_COMPANY_INGAME,
 					STR_CONFIG_SETTING_TYPE_GAME_MENU, STR_CONFIG_SETTING_TYPE_GAME_INGAME,
 				};
-				for (uint i = 0; i < lengthof(setting_types); i++) {
-					SetDParam(0, setting_types[i]);
+				for (const auto &setting_type : setting_types) {
+					SetDParam(0, setting_type);
 					size.width = std::max(size.width, GetStringBoundingBox(STR_CONFIG_SETTING_TYPE).width + padding.width);
 				}
 				size.height = 2 * GetCharacterHeight(FS_NORMAL) + WidgetDimensions::scaled.vsep_normal +
diff --git a/src/settingsgen/settingsgen.cpp b/src/settingsgen/settingsgen.cpp
index 60b61364c7..e028f38294 100644
--- a/src/settingsgen/settingsgen.cpp
+++ b/src/settingsgen/settingsgen.cpp
@@ -391,12 +391,11 @@ static bool CompareFiles(const char *n1, const char *n2)
 
 /** Options of settingsgen. */
 static const OptionData _opts[] = {
-	  GETOPT_NOVAL(     'h', "--help"),
-	GETOPT_GENERAL('h', '?', nullptr, ODF_NO_VALUE),
-	  GETOPT_VALUE(     'o', "--output"),
-	  GETOPT_VALUE(     'b', "--before"),
-	  GETOPT_VALUE(     'a', "--after"),
-	GETOPT_END(),
+	{ .type = ODF_NO_VALUE, .id = 'h', .shortname = 'h', .longname = "--help" },
+	{ .type = ODF_NO_VALUE, .id = 'h', .shortname = '?' },
+	{ .type = ODF_HAS_VALUE, .id = 'o', .shortname = 'o', .longname = "--output" },
+	{ .type = ODF_HAS_VALUE, .id = 'b', .shortname = 'b', .longname = "--before" },
+	{ .type = ODF_HAS_VALUE, .id = 'a', .shortname = 'a', .longname = "--after" },
 };
 
 /**
@@ -442,7 +441,7 @@ int CDECL main(int argc, char *argv[])
 	const char *before_file = nullptr;
 	const char *after_file = nullptr;
 
-	GetOptData mgo(argc - 1, argv + 1, _opts);
+	GetOptData mgo(std::span(argv + 1, argc - 1), _opts);
 	for (;;) {
 		int i = mgo.GetOpt();
 		if (i == -1) break;
@@ -479,7 +478,7 @@ int CDECL main(int argc, char *argv[])
 	_stored_output.Clear();
 	_post_amble_output.Clear();
 
-	for (int i = 0; i < mgo.numleft; i++) ProcessIniFile(mgo.argv[i]);
+	for (auto &argument : mgo.arguments) ProcessIniFile(argument);
 
 	/* Write output. */
 	if (output_file == nullptr) {
diff --git a/src/smallmap_gui.cpp b/src/smallmap_gui.cpp
index d9e697f95a..0af326f930 100644
--- a/src/smallmap_gui.cpp
+++ b/src/smallmap_gui.cpp
@@ -1100,16 +1100,16 @@ void SmallMapWindow::RebuildColourIndexIfNecessary()
 	/* Rebuild colour indices if necessary. */
 	if (SmallMapWindow::map_height_limit == _settings_game.construction.map_height_limit) return;
 
-	for (uint n = 0; n < lengthof(_heightmap_schemes); n++) {
+	for (auto &heightmap_scheme : _heightmap_schemes) {
 		/* The heights go from 0 up to and including maximum. */
 		int heights = _settings_game.construction.map_height_limit + 1;
-		_heightmap_schemes[n].height_colours = ReallocT<uint32_t>(_heightmap_schemes[n].height_colours, heights);
+		heightmap_scheme.height_colours = ReallocT<uint32_t>(heightmap_scheme.height_colours, heights);
 
 		for (int z = 0; z < heights; z++) {
-			size_t access_index = (_heightmap_schemes[n].colour_count * z) / heights;
+			size_t access_index = (heightmap_scheme.colour_count * z) / heights;
 
 			/* Choose colour by mapping the range (0..max heightlevel) on the complete colour table. */
-			_heightmap_schemes[n].height_colours[z] = _heightmap_schemes[n].height_colours_base[access_index];
+			heightmap_scheme.height_colours[z] = heightmap_scheme.height_colours_base[access_index];
 		}
 	}
 
diff --git a/src/spriteloader/sprite_file.cpp b/src/spriteloader/sprite_file.cpp
index e5a701ecba..82498cf83e 100644
--- a/src/spriteloader/sprite_file.cpp
+++ b/src/spriteloader/sprite_file.cpp
@@ -24,8 +24,8 @@ static uint8_t GetGRFContainerVersion(SpriteFile &file)
 	if (file.ReadWord() == 0) {
 		/* Check for GRF container version 2, which is identified by the bytes
 		 * '47 52 46 82 0D 0A 1A 0A' at the start of the file. */
-		for (uint i = 0; i < lengthof(_grf_cont_v2_sig); i++) {
-			if (file.ReadByte() != _grf_cont_v2_sig[i]) return 0; // Invalid format
+		for (const auto &expected_sig_byte : _grf_cont_v2_sig) {
+			if (file.ReadByte() != expected_sig_byte) return 0; // Invalid format
 		}
 
 		return 2;
diff --git a/src/strgen/strgen.cpp b/src/strgen/strgen.cpp
index c1806c813f..6e8e7f7d3e 100644
--- a/src/strgen/strgen.cpp
+++ b/src/strgen/strgen.cpp
@@ -494,37 +494,38 @@ static inline char *mkpath(char *buf, const char *last, const char *path, const
  * this for all Windows machines to keep identical behaviour,
  * no matter what your compiler was.
  */
-static inline char *replace_pathsep(char *s)
+static std::string replace_pathsep(std::string s)
 {
-	for (char *c = s; *c != '\0'; c++) if (*c == '/') *c = '\\';
+	for (char &c : s) {
+		if (c == '/') c = '\\';
+	}
 	return s;
 }
 #else
-static inline char *replace_pathsep(char *s) { return s; }
+static std::string replace_pathsep(std::string s) { return s; }
 #endif
 
 /** Options of strgen. */
 static const OptionData _opts[] = {
-	GETOPT_GENERAL('C', '\0', "-export-commands", ODF_NO_VALUE),
-	GETOPT_GENERAL('L', '\0', "-export-plurals",  ODF_NO_VALUE),
-	GETOPT_GENERAL('P', '\0', "-export-pragmas",  ODF_NO_VALUE),
-	  GETOPT_NOVAL(     't',  "--todo"),
-	  GETOPT_NOVAL(     'w',  "--warning"),
-	  GETOPT_NOVAL(     'h',  "--help"),
-	GETOPT_GENERAL('h', '?',  nullptr,            ODF_NO_VALUE),
-	  GETOPT_VALUE(     's',  "--source_dir"),
-	  GETOPT_VALUE(     'd',  "--dest_dir"),
-	GETOPT_END(),
+	{ .type = ODF_NO_VALUE, .id = 'C', .longname = "-export-commands" },
+	{ .type = ODF_NO_VALUE, .id = 'L', .longname = "-export-plurals" },
+	{ .type = ODF_NO_VALUE, .id = 'P', .longname = "-export-pragmas" },
+	{ .type = ODF_NO_VALUE, .id = 't', .shortname = 't', .longname = "--todo" },
+	{ .type = ODF_NO_VALUE, .id = 'w', .shortname = 'w', .longname = "--warning" },
+	{ .type = ODF_NO_VALUE, .id = 'h', .shortname = 'h', .longname = "--help" },
+	{ .type = ODF_NO_VALUE, .id = 'h', .shortname = '?' },
+	{ .type = ODF_HAS_VALUE, .id = 's', .shortname = 's', .longname = "--source_dir" },
+	{ .type = ODF_HAS_VALUE, .id = 'd', .shortname = 'd', .longname = "--dest_dir" },
 };
 
 int CDECL main(int argc, char *argv[])
 {
 	char pathbuf[MAX_PATH];
 	char pathbuf2[MAX_PATH];
-	const char *src_dir = ".";
-	const char *dest_dir = nullptr;
+	std::string src_dir = ".";
+	std::string dest_dir;
 
-	GetOptData mgo(argc - 1, argv + 1, _opts);
+	GetOptData mgo(std::span(argv + 1, argc - 1), _opts);
 	for (;;) {
 		int i = mgo.GetOpt();
 		if (i == -1) break;
@@ -556,9 +557,9 @@ int CDECL main(int argc, char *argv[])
 
 			case 'P':
 				printf("name\tflags\tdefault\tdescription\n");
-				for (size_t j = 0; j < lengthof(_pragmas); j++) {
+				for (const auto &pragma : _pragmas) {
 					printf("\"%s\"\t%s\t\"%s\"\t\"%s\"\n",
-							_pragmas[j][0], _pragmas[j][1], _pragmas[j][2], _pragmas[j][3]);
+							pragma[0], pragma[1], pragma[2], pragma[3]);
 				}
 				return 0;
 
@@ -601,16 +602,16 @@ int CDECL main(int argc, char *argv[])
 		}
 	}
 
-	if (dest_dir == nullptr) dest_dir = src_dir; // if dest_dir is not specified, it equals src_dir
+	if (dest_dir.empty()) dest_dir = src_dir; // if dest_dir is not specified, it equals src_dir
 
 	try {
 		/* strgen has two modes of operation. If no (free) arguments are passed
 		 * strgen generates strings.h to the destination directory. If it is supplied
 		 * with a (free) parameter the program will translate that language to destination
 		 * directory. As input english.txt is parsed from the source directory */
-		if (mgo.numleft == 0) {
-			mkpath(pathbuf, lastof(pathbuf), src_dir, "english.txt");
-			mkpath2(pathbuf2, lastof(pathbuf2), src_dir, "extra", "english.txt");
+		if (mgo.arguments.empty()) {
+			mkpath(pathbuf, lastof(pathbuf), src_dir.c_str(), "english.txt");
+			mkpath2(pathbuf2, lastof(pathbuf2), src_dir.c_str(), "extra", "english.txt");
 
 			/* parse master file */
 			StringData data(TEXT_TAB_END);
@@ -619,41 +620,41 @@ int CDECL main(int argc, char *argv[])
 			if (_errors != 0) return 1;
 
 			/* write strings.h */
-			ottd_mkdir(dest_dir);
-			mkpath(pathbuf, lastof(pathbuf), dest_dir, "strings.h");
+			ottd_mkdir(dest_dir.c_str());
+			mkpath(pathbuf, lastof(pathbuf), dest_dir.c_str(), "strings.h");
 
 			HeaderFileWriter writer(pathbuf);
 			writer.WriteHeader(data);
 			writer.Finalise(data);
 			if (_errors != 0) return 1;
-		} else if (mgo.numleft >= 1) {
+		} else {
 			char *r;
 
-			mkpath(pathbuf, lastof(pathbuf), src_dir, "english.txt");
-			mkpath2(pathbuf2, lastof(pathbuf2), src_dir, "extra", "english.txt");
+			mkpath(pathbuf, lastof(pathbuf), src_dir.c_str(), "english.txt");
+			mkpath2(pathbuf2, lastof(pathbuf2), src_dir.c_str(), "extra", "english.txt");
 
 			StringData data(TEXT_TAB_END);
 			/* parse master file and check if target file is correct */
 			FileStringReader master_reader(data, pathbuf, pathbuf2, true, false);
 			master_reader.ParseFile();
 
-			for (int i = 0; i < mgo.numleft; i++) {
+			for (auto &argument : mgo.arguments) {
 				data.FreeTranslation();
 
-				const char *translation = replace_pathsep(mgo.argv[i]);
-				const char *file = strrchr(translation, PATHSEPCHAR);
+				std::string translation = replace_pathsep(argument);
+				const char *file = strrchr(translation.c_str(), PATHSEPCHAR);
 				const char *translation2 = nullptr;
 				if (file != nullptr) {
-					mkpath2(pathbuf2, lastof(pathbuf2), src_dir, "extra", file + 1);
+					mkpath2(pathbuf2, lastof(pathbuf2), src_dir.c_str(), "extra", file + 1);
 					translation2 = pathbuf2;
 				}
-				FileStringReader translation_reader(data, translation, translation2, false, file == nullptr || strcmp(file + 1, "english.txt") != 0);
+				FileStringReader translation_reader(data, translation.c_str(), translation2, false, file == nullptr || strcmp(file + 1, "english.txt") != 0);
 				translation_reader.ParseFile(); // target file
 				if (_errors != 0) return 1;
 
 				/* get the targetfile, strip any directories and append to destination path */
-				r = strrchr(mgo.argv[i], PATHSEPCHAR);
-				mkpath(pathbuf, lastof(pathbuf), dest_dir, (r != nullptr) ? &r[1] : mgo.argv[i]);
+				r = strrchr(argument, PATHSEPCHAR);
+				mkpath(pathbuf, lastof(pathbuf), dest_dir.c_str(), (r != nullptr) ? &r[1] : argument);
 
 				/* rename the .txt (input-extension) to .lng */
 				r = strrchr(pathbuf, '.');
diff --git a/src/vehicle_gui.cpp b/src/vehicle_gui.cpp
index 7e8897d6fb..52bcbd9b75 100644
--- a/src/vehicle_gui.cpp
+++ b/src/vehicle_gui.cpp
@@ -3089,8 +3089,8 @@ struct VehicleDetailsWindow : Window {
 					STR_VEHICLE_INFO_WEIGHT_POWER_MAX_SPEED_MAX_TE,
 					STR_VEHICLE_INFO_RELIABILITY_BREAKDOWNS
 				};
-				for (uint i = 0; i < lengthof(info_strings); i++) {
-					dim = maxdim(dim, GetStringBoundingBox(info_strings[i]));
+				for (const auto &info_string : info_strings) {
+					dim = maxdim(dim, GetStringBoundingBox(info_string));
 				}
 				StringID last_year_profit_str = EconTime::UsingWallclockUnits() ? STR_VEHICLE_INFO_PROFIT_THIS_PERIOD_LAST_PERIOD : STR_VEHICLE_INFO_PROFIT_THIS_YEAR_LAST_YEAR;
 				if (v->type == VEH_TRAIN && _settings_client.gui.show_train_length_in_details) {
diff --git a/src/video/sdl_v.cpp b/src/video/sdl_v.cpp
index 3fb20e8770..7bcccf5f91 100644
--- a/src/video/sdl_v.cpp
+++ b/src/video/sdl_v.cpp
@@ -187,9 +187,9 @@ static void GetVideoModes()
 
 	_all_modes = (SDL_ListModes(nullptr, SDL_SWSURFACE | (_fullscreen ? SDL_FULLSCREEN : 0)) == (void*)-1);
 	if (modes == (void*)-1) {
-		for (uint i = 0; i < lengthof(_default_resolutions); i++) {
-			if (SDL_VideoModeOK(_default_resolutions[i].width, _default_resolutions[i].height, 8, SDL_FULLSCREEN) != 0) {
-				_resolutions.push_back(_default_resolutions[i]);
+		for (const auto &default_resolution : _default_resolutions) {
+			if (SDL_VideoModeOK(default_resolution.width, default_resolution.height, 8, SDL_FULLSCREEN) != 0) {
+				_resolutions.push_back(default_resolution);
 			}
 		}
 	} else {
diff --git a/src/viewport.cpp b/src/viewport.cpp
index ab8cb5cc25..14d44737b4 100644
--- a/src/viewport.cpp
+++ b/src/viewport.cpp
@@ -6761,9 +6761,9 @@ static ViewportSSCSS _vp_sprite_sorters[] = {
 /** Choose the "best" sprite sorter and set _vp_sprite_sorter. */
 void InitializeSpriteSorter()
 {
-	for (uint i = 0; i < lengthof(_vp_sprite_sorters); i++) {
-		if (_vp_sprite_sorters[i].fct_checker()) {
-			_vp_sprite_sorter = _vp_sprite_sorters[i].fct_sorter;
+	for (const auto &sprite_sorter : _vp_sprite_sorters) {
+		if (sprite_sorter.fct_checker()) {
+			_vp_sprite_sorter = sprite_sorter.fct_sorter;
 			break;
 		}
 	}