diff --git a/include/yaml-cpp/node/detail/node.h b/include/yaml-cpp/node/detail/node.h
index 4d96b5c..fcd72da 100644
--- a/include/yaml-cpp/node/detail/node.h
+++ b/include/yaml-cpp/node/detail/node.h
@@ -42,9 +42,8 @@ class node {
       return;
 
     m_pRef->mark_defined();
-    for (nodes::iterator it = m_dependencies.begin();
-         it != m_dependencies.end(); ++it)
-      (*it)->mark_defined();
+    for (node* dependency : m_dependencies)
+      dependency->mark_defined();
     m_dependencies.clear();
   }
 
@@ -160,7 +159,7 @@ class node {
 
  private:
   shared_node_ref m_pRef;
-  using nodes = std::set<node *>;
+  using nodes = std::set<node*>;
   nodes m_dependencies;
 };
 }  // namespace detail
diff --git a/src/convert.cpp b/src/convert.cpp
index ec05b77..0ab12b1 100644
--- a/src/convert.cpp
+++ b/src/convert.cpp
@@ -16,8 +16,8 @@ std::string tolower(const std::string& str) {
 
 template <typename T>
 bool IsEntirely(const std::string& str, T func) {
-  for (std::size_t i = 0; i < str.size(); i++)
-    if (!func(str[i]))
+  for (char ch : str)
+    if (!func(ch))
       return false;
 
   return true;
@@ -39,7 +39,7 @@ bool IsFlexibleCase(const std::string& str) {
   std::string rest = str.substr(1);
   return firstcaps && (IsEntirely(rest, IsLower) || IsEntirely(rest, IsUpper));
 }
-}
+}  // namespace
 
 namespace YAML {
 bool convert<bool>::decode(const Node& node, bool& rhs) {
@@ -52,19 +52,22 @@ bool convert<bool>::decode(const Node& node, bool& rhs) {
   static const struct {
     std::string truename, falsename;
   } names[] = {
-      {"y", "n"}, {"yes", "no"}, {"true", "false"}, {"on", "off"},
+      {"y", "n"},
+      {"yes", "no"},
+      {"true", "false"},
+      {"on", "off"},
   };
 
   if (!IsFlexibleCase(node.Scalar()))
     return false;
 
-  for (unsigned i = 0; i < sizeof(names) / sizeof(names[0]); i++) {
-    if (names[i].truename == tolower(node.Scalar())) {
+  for (const auto& name : names) {
+    if (name.truename == tolower(node.Scalar())) {
       rhs = true;
       return true;
     }
 
-    if (names[i].falsename == tolower(node.Scalar())) {
+    if (name.falsename == tolower(node.Scalar())) {
       rhs = false;
       return true;
     }
@@ -72,4 +75,4 @@ bool convert<bool>::decode(const Node& node, bool& rhs) {
 
   return false;
 }
-}
+}  // namespace YAML
diff --git a/src/emitterutils.cpp b/src/emitterutils.cpp
index e348599..3764c2b 100644
--- a/src/emitterutils.cpp
+++ b/src/emitterutils.cpp
@@ -199,11 +199,11 @@ bool IsValidPlainScalar(const std::string& str, FlowType::value flowType,
 
 bool IsValidSingleQuotedScalar(const std::string& str, bool escapeNonAscii) {
   // TODO: check for non-printable characters?
-  for (std::size_t i = 0; i < str.size(); i++) {
-    if (escapeNonAscii && (0x80 <= static_cast<unsigned char>(str[i]))) {
+  for (char ch : str) {
+    if (escapeNonAscii && (0x80 <= static_cast<unsigned char>(ch))) {
       return false;
     }
-    if (str[i] == '\n') {
+    if (ch == '\n') {
       return false;
     }
   }
@@ -217,8 +217,8 @@ bool IsValidLiteralScalar(const std::string& str, FlowType::value flowType,
   }
 
   // TODO: check for non-printable characters?
-  for (std::size_t i = 0; i < str.size(); i++) {
-    if (escapeNonAscii && (0x80 <= static_cast<unsigned char>(str[i]))) {
+  for (char ch : str) {
+    if (escapeNonAscii && (0x80 <= static_cast<unsigned char>(ch))) {
       return false;
     }
   }
diff --git a/src/exp.cpp b/src/exp.cpp
index 695440a..5c3d471 100644
--- a/src/exp.cpp
+++ b/src/exp.cpp
@@ -12,8 +12,7 @@ namespace YAML {
 namespace Exp {
 unsigned ParseHex(const std::string& str, const Mark& mark) {
   unsigned value = 0;
-  for (std::size_t i = 0; i < str.size(); i++) {
-    char ch = str[i];
+  for (char ch : str) {
     int digit = 0;
     if ('a' <= ch && ch <= 'f')
       digit = ch - 'a' + 10;
@@ -132,5 +131,5 @@ std::string Escape(Stream& in) {
   std::stringstream msg;
   throw ParserException(in.mark(), std::string(ErrorMsg::INVALID_ESCAPE) + ch);
 }
-}
-}
+}  // namespace Exp
+}  // namespace YAML
diff --git a/src/ostream_wrapper.cpp b/src/ostream_wrapper.cpp
index 2127dfe..047a9f7 100644
--- a/src/ostream_wrapper.cpp
+++ b/src/ostream_wrapper.cpp
@@ -31,8 +31,8 @@ void ostream_wrapper::write(const std::string& str) {
     std::copy(str.begin(), str.end(), m_buffer.begin() + m_pos);
   }
 
-  for (std::size_t i = 0; i < str.size(); i++) {
-    update_pos(str[i]);
+  for (char ch : str) {
+    update_pos(ch);
   }
 }
 
diff --git a/src/regeximpl.h b/src/regeximpl.h
index 709124f..a742cdc 100644
--- a/src/regeximpl.h
+++ b/src/regeximpl.h
@@ -8,8 +8,8 @@
 #endif
 
 #include "stream.h"
-#include "stringsource.h"
 #include "streamcharsource.h"
+#include "stringsource.h"
 
 namespace YAML {
 // query matches
@@ -106,9 +106,8 @@ inline int RegEx::MatchOpEmpty(const Source& source) const {
 template <>
 inline int RegEx::MatchOpEmpty<StringCharSource>(
     const StringCharSource& source) const {
-  return !source
-             ? 0
-             : -1;  // the empty regex only is successful on the empty string
+  return !source ? 0 : -1;  // the empty regex only is successful on the empty
+                            // string
 }
 
 // MatchOperator
@@ -130,8 +129,8 @@ inline int RegEx::MatchOpRange(const Source& source) const {
 // OrOperator
 template <typename Source>
 inline int RegEx::MatchOpOr(const Source& source) const {
-  for (std::size_t i = 0; i < m_params.size(); i++) {
-    int n = m_params[i].MatchUnchecked(source);
+  for (const RegEx& param : m_params) {
+    int n = param.MatchUnchecked(source);
     if (n >= 0)
       return n;
   }
@@ -169,11 +168,11 @@ inline int RegEx::MatchOpNot(const Source& source) const {
 template <typename Source>
 inline int RegEx::MatchOpSeq(const Source& source) const {
   int offset = 0;
-  for (std::size_t i = 0; i < m_params.size(); i++) {
-    int n = m_params[i].Match(source + offset);  // note Match, not
-                                                 // MatchUnchecked because we
-                                                 // need to check validity after
-                                                 // the offset
+  for (const RegEx& param : m_params) {
+    int n = param.Match(source + offset);  // note Match, not
+                                           // MatchUnchecked because we
+                                           // need to check validity after
+                                           // the offset
     if (n == -1)
       return -1;
     offset += n;
@@ -181,6 +180,6 @@ inline int RegEx::MatchOpSeq(const Source& source) const {
 
   return offset;
 }
-}
+}  // namespace YAML
 
 #endif  // REGEXIMPL_H_62B23520_7C8E_11DE_8A39_0800200C9A66
diff --git a/src/token.h b/src/token.h
index 9a27f3d..9c9a5b7 100644
--- a/src/token.h
+++ b/src/token.h
@@ -53,8 +53,8 @@ struct Token {
 
   friend std::ostream& operator<<(std::ostream& out, const Token& token) {
     out << TokenNames[token.type] << std::string(": ") << token.value;
-    for (std::size_t i = 0; i < token.params.size(); i++)
-      out << std::string(" ") << token.params[i];
+    for (const std::string& param : token.params)
+      out << std::string(" ") << param;
     return out;
   }