diff --git a/main.cpp b/main.cpp
index 2bce6e7..bfcf367 100644
--- a/main.cpp
+++ b/main.cpp
@@ -34,6 +34,7 @@ void save(int freq, char * filename) {
     char * data_do = data.data();
     char *data2 = new char[data.datasize()/2];
 
+    // accelerate in 2 times
 	int i;
     int j = 0;
 	for(i=0;i<data.datasize();i+=2) {
@@ -41,6 +42,7 @@ void save(int freq, char * filename) {
         j++;
     }
     
+    // resize to one size (TOUCH)
     int size = data.datasize()/2;
     if (size > TOUCH) size = TOUCH;
     
@@ -48,6 +50,7 @@ void save(int freq, char * filename) {
 	data.setDatasize(size);
 	data.setData(data2);
 
+    // save with its filename
     data.save(filename);
 }
 
@@ -62,8 +65,10 @@ int play_music(char* filename) {
     char command[256];
     int status;
     
+    /* make a command*/
     sprintf( command, "aplay -c 1 -q -t wav %s", filename );
 
+    /* execute command of play*/
     status = system( command );
      
     return status;
--
libgit2 0.21.2