diff --git a/app/exiv2.cpp b/app/exiv2.cpp
index 65e86019..6f04e6e3 100644
--- a/app/exiv2.cpp
+++ b/app/exiv2.cpp
@@ -742,16 +742,15 @@ int Params::evalDelete(const std::string& optArg) {
   switch (action_) {
     case Action::none:
       action_ = Action::erase;
-      target_ = CommonTarget(0);
+      target_ = static_cast<CommonTarget>(0);
       // fallthrough
     case Action::erase: {
       const auto rc = parseCommonTargets(optArg, "erase");
       if (rc > 0) {
-        target_ |= CommonTarget(rc);
+        target_ |= static_cast<CommonTarget>(rc);
         return 0;
-      } else {
-        return 1;
       }
+      return 1;
     }
     default:
       std::cerr << progname() << ": " << _("Option -d is not compatible with a previous option\n");
@@ -764,16 +763,15 @@ int Params::evalExtract(const std::string& optArg) {
     case Action::none:
     case Action::modify:
       action_ = Action::extract;
-      target_ = CommonTarget(0);
+      target_ = static_cast<CommonTarget>(0);
       // fallthrough
     case Action::extract: {
       const auto rc = parseCommonTargets(optArg, "extract");
       if (rc > 0) {
-        target_ |= CommonTarget(rc);
+        target_ |= static_cast<CommonTarget>(rc);
         return 0;
-      } else {
-        return 1;
       }
+      return 1;
     }
     default:
       std::cerr << progname() << ": " << _("Option -e is not compatible with a previous option\n");
@@ -786,16 +784,15 @@ int Params::evalInsert(const std::string& optArg) {
     case Action::none:
     case Action::modify:
       action_ = Action::insert;
-      target_ = CommonTarget(0);
+      target_ = static_cast<CommonTarget>(0);
       // fallthrough
     case Action::insert: {
       const auto rc = parseCommonTargets(optArg, "insert");
       if (rc > 0) {
-        target_ |= CommonTarget(rc);
+        target_ |= static_cast<CommonTarget>(rc);
         return 0;
-      } else {
-        return 1;
       }
+      return 1;
     }
     default:
       std::cerr << progname() << ": " << _("Option -i is not compatible with a previous option\n");
@@ -1139,7 +1136,7 @@ void printUnrecognizedArgument(const char argc, const std::string& action) {
 
 int64_t parseCommonTargets(const std::string& optArg, const std::string& action) {
   int64_t rc = 0;
-  Params::CommonTarget target = Params::CommonTarget(0);
+  auto target = static_cast<Params::CommonTarget>(0);
   Params::CommonTarget all = Params::ctExif | Params::ctIptc | Params::ctComment | Params::ctXmp;
   Params::CommonTarget extra = Params::ctXmpSidecar | Params::ctExif | Params::ctIptc | Params::ctXmp;
   for (size_t i = 0; rc == 0 && i < optArg.size(); ++i) {
@@ -1175,7 +1172,7 @@ int64_t parseCommonTargets(const std::string& optArg, const std::string& action)
         target |= extra;  // -eX
         if (i > 0) {      // -eXX or -iXX
           target |= Params::ctXmpRaw;
-          target = Params::CommonTarget(target & ~extra);  // turn off those bits
+          target = static_cast<Params::CommonTarget>(target & ~extra);  // turn off those bits
         }
         break;
 
@@ -1196,7 +1193,7 @@ int64_t parseCommonTargets(const std::string& optArg, const std::string& action)
         break;
     }
   }
-  return rc ? rc : int64_t(target);
+  return rc ? rc : static_cast<int64_t>(target);
 }
 
 int parsePreviewNumbers(Params::PreviewNumbers& previewNumbers, const std::string& optArg, int j) {
diff --git a/app/exiv2app.hpp b/app/exiv2app.hpp
index cae67770..5c278f9a 100644
--- a/app/exiv2app.hpp
+++ b/app/exiv2app.hpp
@@ -122,7 +122,7 @@ class Params : public Util::Getopt {
   static Params& instance();
 
   //! Prevent copy-construction: not implemented.
-  ~Params() = default;
+  ~Params() override = default;
   Params(const Params&) = delete;
   Params& operator=(const Params&) = delete;
 
diff --git a/include/exiv2/bmffimage.hpp b/include/exiv2/bmffimage.hpp
index d7963837..7fc29479 100644
--- a/include/exiv2/bmffimage.hpp
+++ b/include/exiv2/bmffimage.hpp
@@ -14,7 +14,7 @@
 // namespace extensions
 namespace Exiv2 {
 EXIV2API bool enableBMFF(bool enable = true);
-}
+}  // namespace Exiv2
 
 #ifdef EXV_ENABLE_BMFF
 namespace Exiv2 {
diff --git a/include/exiv2/properties.hpp b/include/exiv2/properties.hpp
index 36dc8179..295306fb 100644
--- a/include/exiv2/properties.hpp
+++ b/include/exiv2/properties.hpp
@@ -8,6 +8,7 @@
 
 // included header files
 #include <mutex>
+
 #include "datasets.hpp"
 
 // *****************************************************************************
diff --git a/include/exiv2/webpimage.hpp b/include/exiv2/webpimage.hpp
index 317e5986..dd59142f 100644
--- a/include/exiv2/webpimage.hpp
+++ b/include/exiv2/webpimage.hpp
@@ -54,7 +54,7 @@ class EXIV2API WebPImage : public Image {
   [[nodiscard]] std::string mimeType() const override;
   //@}
 
-  ~WebPImage() = default;
+  ~WebPImage() override = default;
   //! Copy constructor
   WebPImage(const WebPImage&) = delete;
   //! Assignment operator
diff --git a/include/exiv2/xmp_exiv2.hpp b/include/exiv2/xmp_exiv2.hpp
index ec3d02c6..f7e78a7c 100644
--- a/include/exiv2/xmp_exiv2.hpp
+++ b/include/exiv2/xmp_exiv2.hpp
@@ -58,16 +58,11 @@ class EXIV2API Xmpdatum : public Metadatum {
            Calls setValue(const std::string&).
    */
   Xmpdatum& operator=(const std::string& value);
-  /*!
-    @brief Assign const char* \em value to the %Xmpdatum.
-           Calls operator=(const std::string&).
-   */
-  Xmpdatum& operator=(const char* value);
   /*!
     @brief Assign a boolean \em value to the %Xmpdatum.
            Translates the value to a string "true" or "false".
    */
-  Xmpdatum& operator=(const bool& value);
+  Xmpdatum& operator=(bool value);
   /*!
     @brief Assign a \em value of any type with an output operator
            to the %Xmpdatum. Calls operator=(const std::string&).
@@ -227,23 +222,23 @@ class EXIV2API XmpData {
   //! are we to use the packet?
   [[nodiscard]] bool usePacket() const {
     return usePacket_;
-  };
+  }
 
   //! set usePacket_
   bool usePacket(bool b) {
     bool r = usePacket_;
     usePacket_ = b;
     return r;
-  };
+  }
   //! setPacket
   void setPacket(std::string xmpPacket) {
     xmpPacket_ = std::move(xmpPacket);
     usePacket(false);
-  };
+  }
   // ! getPacket
   [[nodiscard]] const std::string& xmpPacket() const {
     return xmpPacket_;
-  };
+  }
 
   //@}
 
@@ -404,11 +399,7 @@ class EXIV2API XmpParser {
 // *****************************************************************************
 // free functions, template and inline definitions
 
-inline Xmpdatum& Xmpdatum::operator=(const char* value) {
-  return Xmpdatum::operator=(std::string(value));
-}
-
-inline Xmpdatum& Xmpdatum::operator=(const bool& value) {
+inline Xmpdatum& Xmpdatum::operator=(bool value) {
   return operator=(value ? "True" : "False");
 }
 
diff --git a/src/convert.cpp b/src/convert.cpp
index fbe53d60..93f49182 100644
--- a/src/convert.cpp
+++ b/src/convert.cpp
@@ -1284,7 +1284,7 @@ std::string Converter::computeExifDigest(bool tiff) {
 }
 #else
 std::string Converter::computeExifDigest(bool) {
-  return std::string("");
+  return {};
 }
 #endif
 
diff --git a/src/nikonmn_int.cpp b/src/nikonmn_int.cpp
index f636f03b..07e485ac 100644
--- a/src/nikonmn_int.cpp
+++ b/src/nikonmn_int.cpp
@@ -3226,9 +3226,9 @@ std::ostream& Nikon3MakerNote::print0x009e(std::ostream& os, const Value& value,
     std::string d = s.empty() ? "" : "; ";
     const TagDetails* td = find(nikonRetouchHistory, l);
     if (td) {
-      s = std::string(exvGettext(td->label_)) + d + s;
+      s = std::string(exvGettext(td->label_)).append(d).append(s);
     } else {
-      s = std::string(_("Unknown")) + std::string(" (") + toString(l) + std::string(")") + d + s;
+      s = std::string(_("Unknown")).append(" (").append(toString(l)).append(")").append(d).append(s);
     }
   }
   return os << s;
diff --git a/src/pngchunk_int.cpp b/src/pngchunk_int.cpp
index e7aec605..2d7cdcbd 100644
--- a/src/pngchunk_int.cpp
+++ b/src/pngchunk_int.cpp
@@ -318,31 +318,25 @@ void PngChunk::parseChunkContent(Image* pImage, const byte* key, size_t keySize,
 }  // PngChunk::parseChunkContent
 
 std::string PngChunk::makeMetadataChunk(const std::string& metadata, MetadataId type) {
-  std::string chunk;
   std::string rawProfile;
 
   switch (type) {
     case mdComment:
-      chunk = makeUtf8TxtChunk("Description", metadata, true);
-      break;
+      return makeUtf8TxtChunk("Description", metadata, true);
     case mdExif:
       rawProfile = writeRawProfile(metadata, "exif");
-      chunk = makeAsciiTxtChunk("Raw profile type exif", rawProfile, true);
-      break;
+      return makeAsciiTxtChunk("Raw profile type exif", rawProfile, true);
     case mdIptc:
       rawProfile = writeRawProfile(metadata, "iptc");
-      chunk = makeAsciiTxtChunk("Raw profile type iptc", rawProfile, true);
-      break;
+      return makeAsciiTxtChunk("Raw profile type iptc", rawProfile, true);
     case mdXmp:
-      chunk = makeUtf8TxtChunk("XML:com.adobe.xmp", metadata, false);
-      break;
+      return makeUtf8TxtChunk("XML:com.adobe.xmp", metadata, false);
     case mdIccProfile:
-      break;
     case mdNone:
-      break;
+      return {};
   }
 
-  return chunk;
+  return {};
 
 }  // PngChunk::makeMetadataChunk
 
diff --git a/src/tags.cpp b/src/tags.cpp
index f084dd9d..13c231c0 100644
--- a/src/tags.cpp
+++ b/src/tags.cpp
@@ -302,7 +302,7 @@ std::string ExifKey::tagLabel() const {
 
 std::string ExifKey::tagDesc() const {
   if (!p_->tagInfo_ || p_->tagInfo_->tag_ == 0xffff)
-    return "";
+    return {};
   return _(p_->tagInfo_->desc_);
 }
 
diff --git a/src/types.cpp b/src/types.cpp
index 1ec865e4..ff6bc48b 100644
--- a/src/types.cpp
+++ b/src/types.cpp
@@ -178,7 +178,8 @@ byte* Exiv2::DataBuf::data(size_t offset) {
 const byte* Exiv2::DataBuf::c_data(size_t offset) const {
   if (pData_.empty()) {
     return nullptr;
-  } else if (offset >= pData_.size()) {
+  }
+  if (offset >= pData_.size()) {
     throw std::out_of_range("Overflow in Exiv2::DataBuf::c_data");
   }
   return &pData_[offset];
diff --git a/src/utils.hpp b/src/utils.hpp
index 1e16648d..c385b07d 100644
--- a/src/utils.hpp
+++ b/src/utils.hpp
@@ -14,7 +14,7 @@ constexpr bool startsWith(std::string_view s, std::string_view start) {
 std::string upper(const std::string& str);
 
 /// @brief Returns the lowercase version of \b str
-std::string lower(const std::string& str);
+std::string lower(const std::string& a);
 
 }  // namespace Exiv2::Internal
 
diff --git a/src/xmp.cpp b/src/xmp.cpp
index cb4f422d..ed54b340 100644
--- a/src/xmp.cpp
+++ b/src/xmp.cpp
@@ -53,7 +53,7 @@ class XMLValidator {
   // error out if the depth exceeds this limit.
   static const size_t max_recursion_limit_ = 1000;
 
-  const XML_Parser parser_;
+  XML_Parser parser_;
 
  public:
   // Runs an XML parser on `buf`. Throws an exception if the XML is invalid.