Fix doc sample typos in header and README

* iterations() is a method
* int64_t fix in a couple of places
diff --git a/README.md b/README.md
index b3427ab..d95d276 100644
--- a/README.md
+++ b/README.md
@@ -44,7 +44,8 @@
   memset(src, 'x', state.range_x());
   while (state.KeepRunning())
     memcpy(dst, src, state.range_x());
-  state.SetBytesProcessed(int64_t(state.iterations) * int64_t(state.range_x()));
+  state.SetBytesProcessed(int64_t(state.iterations()) *
+                          int64_t(state.range_x()));
   delete[] src;
   delete[] dst;
 }