diff --git a/serial_io.cpp b/serial_io.cpp
index d4f65f4..e6006d6 100644
--- a/serial_io.cpp
+++ b/serial_io.cpp
@@ -5,13 +5,13 @@ struct termios toptions;
 void sWrite(int port, char string[], size_t length)
 {
     if(port != -1) write(port, string, length);
-    else for( int j = 0; j < length; j++  )std::cout<<string[j];
+    else for( size_t j = 0; j < length; j++  )std::cout<<string[j];
 }
 
 void sWrite(int port, const char string[], size_t length)
 {
     if(port != -1) write(port, string, length);
-    else for( int j = 0; j < length; j++  )std::cout<<string[j];
+    else for( size_t j = 0; j < length; j++  )std::cout<<string[j];
 }
 
 ssize_t sRead(int port, void *buf, size_t count)
@@ -33,7 +33,7 @@ int serialport_init(const char* device, int baud)
         {
         perror("init_serialport: Couldn't get term attributes");
         return -1;
-        
+        }
     cfsetispeed(&toptions, baud);
     cfsetospeed(&toptions, baud);
     // 8N1