Updated some C++ implementation code to be stricter by adding appropriate 'using' directives for C standard library types.

cpp/QrCode.cpp

@@ -28,6 +28,10 @@
 #include "BitBuffer.hpp"
 #include "QrCode.hpp"
 
+using std::int8_t;
+using std::uint8_t;
+using std::size_t;
+
 
 namespace qrcodegen {
 

cpp/QrCodeGeneratorDemo.cpp

@@ -31,6 +31,7 @@
 #include <vector>
 #include "QrCode.hpp"
 
+using std::uint8_t;
 using qrcodegen::QrCode;
 using qrcodegen::QrSegment;
 

cpp/QrSegment.cpp

@@ -26,6 +26,8 @@
 #include "BitBuffer.hpp"
 #include "QrSegment.hpp"
 
+using std::uint8_t;
+
 
 namespace qrcodegen {