diff --git a/src/lib_json/json_reader.cpp b/src/lib_json/json_reader.cpp
index fe79634..aa5156f 100644
--- a/src/lib_json/json_reader.cpp
+++ b/src/lib_json/json_reader.cpp
@@ -880,7 +880,7 @@ bool Reader::pushError(const Value& value,
   return true;
 }
 
-bool Reader::good() const { return !errors_.size(); }
+bool Reader::good() const { return errors_.empty(); }
 
 // exact copy of Features
 class OurFeatures {
@@ -1895,7 +1895,7 @@ bool OurReader::pushError(const Value& value,
   return true;
 }
 
-bool OurReader::good() const { return !errors_.size(); }
+bool OurReader::good() const { return errors_.empty(); }
 
 class OurCharReader : public CharReader {
   bool const collectComments_;
@@ -1961,7 +1961,7 @@ bool CharReaderBuilder::validate(Json::Value* invalid) const {
       inv[key] = settings_[key];
     }
   }
-  return 0u == inv.size();
+  return inv.empty();
 }
 Value& CharReaderBuilder::operator[](const JSONCPP_STRING& key) {
   return settings_[key];
diff --git a/src/lib_json/json_value.cpp b/src/lib_json/json_value.cpp
index 1aec87f..c7fcfa4 100644
--- a/src/lib_json/json_value.cpp
+++ b/src/lib_json/json_value.cpp
@@ -889,8 +889,8 @@ bool Value::isConvertibleTo(ValueType other) const {
     return (isNumeric() && asDouble() == 0.0) ||
            (type_ == booleanValue && value_.bool_ == false) ||
            (type_ == stringValue && asString().empty()) ||
-           (type_ == arrayValue && value_.map_->size() == 0) ||
-           (type_ == objectValue && value_.map_->size() == 0) ||
+           (type_ == arrayValue && value_.map_->empty()) ||
+           (type_ == objectValue && value_.map_->empty()) ||
            type_ == nullValue;
   case intValue:
     return isInt() ||
diff --git a/src/lib_json/json_writer.cpp b/src/lib_json/json_writer.cpp
index 4f77121..7138b7a 100644
--- a/src/lib_json/json_writer.cpp
+++ b/src/lib_json/json_writer.cpp
@@ -551,7 +551,7 @@ bool StyledWriter::isMultilineArray(const Value& value) {
   for (ArrayIndex index = 0; index < size && !isMultiLine; ++index) {
     const Value& childValue = value[index];
     isMultiLine = ((childValue.isArray() || childValue.isObject()) &&
-                   childValue.size() > 0);
+                   !childValue.empty());
   }
   if (!isMultiLine) // check if line length > max line length
   {
@@ -774,7 +774,7 @@ bool StyledStreamWriter::isMultilineArray(const Value& value) {
   for (ArrayIndex index = 0; index < size && !isMultiLine; ++index) {
     const Value& childValue = value[index];
     isMultiLine = ((childValue.isArray() || childValue.isObject()) &&
-                   childValue.size() > 0);
+                   !childValue.empty());
   }
   if (!isMultiLine) // check if line length > max line length
   {
@@ -1059,7 +1059,7 @@ bool BuiltStyledStreamWriter::isMultilineArray(Value const& value) {
   for (ArrayIndex index = 0; index < size && !isMultiLine; ++index) {
     Value const& childValue = value[index];
     isMultiLine = ((childValue.isArray() || childValue.isObject()) &&
-                   childValue.size() > 0);
+                   !childValue.empty());
   }
   if (!isMultiLine) // check if line length > max line length
   {
@@ -1226,7 +1226,7 @@ bool StreamWriterBuilder::validate(Json::Value* invalid) const {
       inv[key] = settings_[key];
     }
   }
-  return 0u == inv.size();
+  return inv.empty();
 }
 Value& StreamWriterBuilder::operator[](const JSONCPP_STRING& key) {
   return settings_[key];
diff --git a/src/test_lib_json/main.cpp b/src/test_lib_json/main.cpp
index 23da4b3..4dfca75 100644
--- a/src/test_lib_json/main.cpp
+++ b/src/test_lib_json/main.cpp
@@ -1818,7 +1818,7 @@ JSONTEST_FIXTURE(StreamWriterTest, dropNullPlaceholders) {
   b.settings_["dropNullPlaceholders"] = false;
   JSONTEST_ASSERT(Json::writeString(b, nullValue) == "null");
   b.settings_["dropNullPlaceholders"] = true;
-  JSONTEST_ASSERT(Json::writeString(b, nullValue) == "");
+  JSONTEST_ASSERT(Json::writeString(b, nullValue).empty());
 }
 
 JSONTEST_FIXTURE(StreamWriterTest, writeZeroes) {
@@ -1850,8 +1850,8 @@ JSONTEST_FIXTURE(ReaderTest, parseWithNoErrors) {
   Json::Value root;
   bool ok = reader.parse("{ \"property\" : \"value\" }", root);
   JSONTEST_ASSERT(ok);
-  JSONTEST_ASSERT(reader.getFormattedErrorMessages().size() == 0);
-  JSONTEST_ASSERT(reader.getStructuredErrors().size() == 0);
+  JSONTEST_ASSERT(reader.getFormattedErrorMessages().empty());
+  JSONTEST_ASSERT(reader.getStructuredErrors().empty());
 }
 
 JSONTEST_FIXTURE(ReaderTest, parseWithNoErrorsTestingOffsets) {
@@ -1862,8 +1862,8 @@ JSONTEST_FIXTURE(ReaderTest, parseWithNoErrorsTestingOffsets) {
                          "null, \"false\" : false }",
                          root);
   JSONTEST_ASSERT(ok);
-  JSONTEST_ASSERT(reader.getFormattedErrorMessages().size() == 0);
-  JSONTEST_ASSERT(reader.getStructuredErrors().size() == 0);
+  JSONTEST_ASSERT(reader.getFormattedErrorMessages().empty());
+  JSONTEST_ASSERT(reader.getStructuredErrors().empty());
   JSONTEST_ASSERT(root["property"].getOffsetStart() == 15);
   JSONTEST_ASSERT(root["property"].getOffsetLimit() == 34);
   JSONTEST_ASSERT(root["property"][0].getOffsetStart() == 16);
@@ -1944,7 +1944,7 @@ JSONTEST_FIXTURE(CharReaderTest, parseWithNoErrors) {
   char const doc[] = "{ \"property\" : \"value\" }";
   bool ok = reader->parse(doc, doc + std::strlen(doc), &root, &errs);
   JSONTEST_ASSERT(ok);
-  JSONTEST_ASSERT(errs.size() == 0);
+  JSONTEST_ASSERT(errs.empty());
   delete reader;
 }
 
@@ -1958,7 +1958,7 @@ JSONTEST_FIXTURE(CharReaderTest, parseWithNoErrorsTestingOffsets) {
                      "null, \"false\" : false }";
   bool ok = reader->parse(doc, doc + std::strlen(doc), &root, &errs);
   JSONTEST_ASSERT(ok);
-  JSONTEST_ASSERT(errs.size() == 0);
+  JSONTEST_ASSERT(errs.empty());
   delete reader;
 }
 
@@ -2014,7 +2014,7 @@ JSONTEST_FIXTURE(CharReaderTest, parseWithStackLimit) {
     JSONCPP_STRING errs;
     bool ok = reader->parse(doc, doc + std::strlen(doc), &root, &errs);
     JSONTEST_ASSERT(ok);
-    JSONTEST_ASSERT(errs == "");
+    JSONTEST_ASSERT(errs.empty());
     JSONTEST_ASSERT_EQUAL("value", root["property"]);
     delete reader;
   }
@@ -2061,7 +2061,7 @@ JSONTEST_FIXTURE(CharReaderFailIfExtraTest, issue164) {
     JSONCPP_STRING errs;
     bool ok = reader->parse(doc, doc + std::strlen(doc), &root, &errs);
     JSONTEST_ASSERT(ok);
-    JSONTEST_ASSERT(errs == "");
+    JSONTEST_ASSERT(errs.empty());
     JSONTEST_ASSERT_EQUAL("property", root);
     delete reader;
   }
@@ -2176,7 +2176,7 @@ JSONTEST_FIXTURE(CharReaderAllowDropNullTest, issue178) {
     char const doc[] = "[]";
     bool ok = reader->parse(doc, doc + std::strlen(doc), &root, &errs);
     JSONTEST_ASSERT(ok);
-    JSONTEST_ASSERT(errs == "");
+    JSONTEST_ASSERT(errs.empty());
     JSONTEST_ASSERT_EQUAL(0u, root.size());
     JSONTEST_ASSERT_EQUAL(Json::arrayValue, root);
   }
@@ -2184,7 +2184,7 @@ JSONTEST_FIXTURE(CharReaderAllowDropNullTest, issue178) {
     char const doc[] = "[null]";
     bool ok = reader->parse(doc, doc + std::strlen(doc), &root, &errs);
     JSONTEST_ASSERT(ok);
-    JSONTEST_ASSERT(errs == "");
+    JSONTEST_ASSERT(errs.empty());
     JSONTEST_ASSERT_EQUAL(1u, root.size());
   }
   {
@@ -2212,7 +2212,7 @@ JSONTEST_FIXTURE(CharReaderAllowDropNullTest, issue178) {
     char const doc[] = "[,null]";
     bool ok = reader->parse(doc, doc + std::strlen(doc), &root, &errs);
     JSONTEST_ASSERT(ok);
-    JSONTEST_ASSERT(errs == "");
+    JSONTEST_ASSERT(errs.empty());
     JSONTEST_ASSERT_EQUAL(2u, root.size());
   }
   {
@@ -2240,7 +2240,7 @@ JSONTEST_FIXTURE(CharReaderAllowDropNullTest, issue178) {
     char const doc[] = "[,,null]";
     bool ok = reader->parse(doc, doc + std::strlen(doc), &root, &errs);
     JSONTEST_ASSERT(ok);
-    JSONTEST_ASSERT(errs == "");
+    JSONTEST_ASSERT(errs.empty());
     JSONTEST_ASSERT_EQUAL(3u, root.size());
   }
   {
@@ -2263,7 +2263,7 @@ JSONTEST_FIXTURE(CharReaderAllowDropNullTest, issue178) {
     char const doc[] = "[,,,[]]";
     bool ok = reader->parse(doc, doc + std::strlen(doc), &root, &errs);
     JSONTEST_ASSERT(ok);
-    JSONTEST_ASSERT(errs == "");
+    JSONTEST_ASSERT(errs.empty());
     JSONTEST_ASSERT_EQUAL(4u, root.size());
     JSONTEST_ASSERT_EQUAL(Json::arrayValue, root[3u]);
   }