diff --git a/examples/github-issues.cc b/examples/github-issues.cc
index 0235b96..60a4aab 100644
--- a/examples/github-issues.cc
+++ b/examples/github-issues.cc
@@ -35,7 +35,7 @@ typedef struct {
 
 MEMFILE *memfopen() {
   MEMFILE *mf = (MEMFILE *)malloc(sizeof(MEMFILE));
-  mf->data = NULL;
+  mf->data = nullptr;
   mf->size = 0;
   return mf;
 }
diff --git a/picojson.h b/picojson.h
index 76742fe..a31abf3 100644
--- a/picojson.h
+++ b/picojson.h
@@ -1103,7 +1103,7 @@ template <typename Iter> inline std::string parse(value &out, Iter &pos, const I
 
 template <typename Context, typename Iter> inline Iter _parse(Context &ctx, const Iter &first, const Iter &last, std::string *err) {
   input<Iter> in(first, last);
-  if (!_parse(ctx, in) && err != NULL) {
+  if (!_parse(ctx, in) && err != nullptr) {
     char buf[64];
     SNPRINTF(buf, sizeof(buf), "syntax error at line %d near: ", in.line());
     *err = buf;