diff --git a/examples/cpp/wav.h b/examples/cpp/wav.h
index 249d7e3..e6ef442 100644
--- a/examples/cpp/wav.h
+++ b/examples/cpp/wav.h
@@ -12,10 +12,10 @@
 // See the License for the specific language governing permissions and
 // limitations under the License.
 
-
 #ifndef FRONTEND_WAV_H_
 #define FRONTEND_WAV_H_
 
+
 #include <assert.h>
 #include <stdint.h>
 #include <stdio.h>
@@ -24,6 +24,8 @@
 
 #include <string>
 
+#include <iostream>
+
 // #include "utils/log.h"
 
 namespace wav {
@@ -230,6 +232,6 @@ class WavWriter {
   int bits_per_sample_;
 };
 
-}  // namespace wenet
+}  // namespace wav
 
 #endif  // FRONTEND_WAV_H_