diff --git a/backends/barcode/QrEncode.cpp b/backends/barcode/QrEncode.cpp
index 543f0bf..2772660 100644
--- a/backends/barcode/QrEncode.cpp
+++ b/backends/barcode/QrEncode.cpp
@@ -60,7 +60,7 @@ namespace glabels
 			bool QrCode::encode( const std::string& cookedData, glbarcode::Matrix<bool>& encodedData )
 			{
 				QRcode *qrcode = QRcode_encodeString( cookedData.c_str(), 0, QR_ECLEVEL_M, QR_MODE_8, 1 );
-				if ( qrcode == NULL )
+				if ( qrcode == nullptr )
 				{
 					return false;
 				}
diff --git a/glbarcode/BarcodeDataMatrix.cpp b/glbarcode/BarcodeDataMatrix.cpp
index 49dc5ee..f78393d 100644
--- a/glbarcode/BarcodeDataMatrix.cpp
+++ b/glbarcode/BarcodeDataMatrix.cpp
@@ -22,7 +22,7 @@
 
 #include "Constants.h"
 
-#include <stdint.h>
+#include <cstdint>
 #include <vector>
 #include <cctype>
 #include <algorithm>
diff --git a/glbarcode/BarcodeOnecode.h b/glbarcode/BarcodeOnecode.h
index bf8ba83..0208129 100644
--- a/glbarcode/BarcodeOnecode.h
+++ b/glbarcode/BarcodeOnecode.h
@@ -24,7 +24,7 @@
 
 #include "Barcode1dBase.h"
 
-#include <stdint.h>
+#include <cstdint>
 
 
 namespace glbarcode