diff --git a/demos/src/ttdebug.c b/demos/src/ttdebug.c
index dc4a70a30..5239a82d7 100644
--- a/demos/src/ttdebug.c
+++ b/demos/src/ttdebug.c
@@ -811,7 +811,7 @@ TT_CodeRange_Tag  debug_coderange = tt_coderange_glyph;
   {
     FT_Int    A, diff, key;
     FT_Long   next_IP;
-    FT_Char   ch, oldch, *temp;
+    FT_Char   ch, oldch = '\0', *temp;
 
     TT_Error  error = 0;