diff --git a/src/jsontestrunner/main.cpp b/src/jsontestrunner/main.cpp
index 3b5e21a..28691a2 100644
--- a/src/jsontestrunner/main.cpp
+++ b/src/jsontestrunner/main.cpp
@@ -16,7 +16,7 @@
 #include <algorithm> // sort
 #include <json/json.h>
 #include <sstream>
-#include <stdio.h>
+#include <cstdio>
 
 struct Options {
   JSONCPP_STRING path;
diff --git a/src/lib_json/json_value.cpp b/src/lib_json/json_value.cpp
index a95032d..81640ea 100644
--- a/src/lib_json/json_value.cpp
+++ b/src/lib_json/json_value.cpp
@@ -10,7 +10,7 @@
 #endif // if !defined(JSON_IS_AMALGAMATION)
 #include <cassert>
 #include <cstring>
-#include <math.h>
+#include <cmath>
 #include <sstream>
 #include <utility>
 #ifdef JSON_USE_CPPTL
diff --git a/src/lib_json/json_writer.cpp b/src/lib_json/json_writer.cpp
index 26ee8b7..3a7fd8e 100644
--- a/src/lib_json/json_writer.cpp
+++ b/src/lib_json/json_writer.cpp
@@ -28,8 +28,8 @@
 #endif
 
 #else
-#include <math.h>
-#include <stdio.h>
+#include <cmath>
+#include <cstdio>
 
 #if defined(_MSC_VER)
 #if !defined(isnan)
diff --git a/src/test_lib_json/jsontest.cpp b/src/test_lib_json/jsontest.cpp
index 76e6832..5e04aa4 100644
--- a/src/test_lib_json/jsontest.cpp
+++ b/src/test_lib_json/jsontest.cpp
@@ -5,7 +5,7 @@
 
 #define _CRT_SECURE_NO_WARNINGS 1 // Prevents deprecation warning with MSVC
 #include "jsontest.h"
-#include <stdio.h>
+#include <cstdio>
 #include <string>
 
 #if defined(_MSC_VER)
diff --git a/src/test_lib_json/jsontest.h b/src/test_lib_json/jsontest.h
index 58c5251..48761c5 100644
--- a/src/test_lib_json/jsontest.h
+++ b/src/test_lib_json/jsontest.h
@@ -11,7 +11,7 @@
 #include <json/value.h>
 #include <json/writer.h>
 #include <sstream>
-#include <stdio.h>
+#include <cstdio>
 #include <string>
 
 // //////////////////////////////////////////////////////////////////