diff --git a/.gitignore b/.gitignore
index 7fae9e0..9a28a81 100644
--- a/.gitignore
+++ b/.gitignore
@@ -34,4 +34,4 @@
 
 pcg32-demo
 pcg32-global-demo
-pcg32x2-demo
\ No newline at end of file
+pcg32x2-demo
diff --git a/README.md b/README.md
index da48795..1a6a0c5 100644
--- a/README.md
+++ b/README.md
@@ -22,7 +22,7 @@ at the sample code -- hopefully it should be fairly self explanatory.
 There is no library to build.  Just use the code.  You can however build the
 three demo programs.
 
-The code is written in C89-style C with no significant platform dependencies.
+The code is written in C99-style C with no significant platform dependencies.
 On a Unix-style system (e.g., Linux, Mac OS X), or any system with `make`,
 you should be able to just type type
 
@@ -52,4 +52,4 @@ To produce different output, run
     ./pcg32-demo -r
 
 You can also pass an integer count to specify how may rounds of output you
-would like.
\ No newline at end of file
+would like.
diff --git a/pcg32x2-demo.c b/pcg32x2-demo.c
index f2d820f..50cd8ba 100644
--- a/pcg32x2-demo.c
+++ b/pcg32x2-demo.c
@@ -25,13 +25,14 @@
  * This file was mechanically generated from tests/check-pcg32.c
  */
 
-#include <stdio.h>
+#include <inttypes.h>
+#include <stdbool.h>
 #include <stddef.h>
-#include <stdlib.h>
 #include <stdint.h>
-#include <stdbool.h>
-#include <time.h>
+#include <stdio.h>
+#include <stdlib.h>
 #include <string.h>
+#include <time.h>
 
 #include "pcg_basic.h"
 
@@ -152,7 +153,7 @@ int main(int argc, char** argv)
         for (i = 0; i < 6; ++i) {
             if (i > 0 && i % 3 == 0)
                 printf("\n\t");
-            printf(" 0x%016llx", pcg32x2_random_r(&rng));
+            printf(" 0x%016" PRIx64, pcg32x2_random_r(&rng));
         }
         printf("\n");