add print file size

include/arg_func.hpp

@@ -21,6 +21,7 @@ enum class Arg
 	Username,		 // update username
 	Name,				 // update label name
 	File,				 // select save file
+	Size				 // show size of file
 };
 
 Arg get_args(int argc, char **argv, char **label);
@@ -45,4 +46,6 @@ void arg_show(Buffer &decrypted_buffer, const char *label);
 
 void arg_file(Buffer &decrypted_buffer, Buffer &encrypted_buffer, const char *label, Cryptography &crypto, std::string &save_location_path);
 
+void arg_size(Buffer &encrypted_buffer);
+
 #endif