diff --git a/util.c b/util.c
index 449d4bf439..6c18543347 100644
--- a/util.c
+++ b/util.c
@@ -783,9 +783,9 @@ ruby_strtod(string, endPtr)
      * and also locate the decimal point.
      */
 
-    for ( ; c = *p; p++) {
+    for ( ; (c = *p) != '\0'; p++) {
 	if (!ISDIGIT(c)) {
-	    if (c != '.' || hasPoint) {
+	    if (c != '.' || hasPoint || !ISDIGIT(p[1])) {
 		break;
 	    }
 	    hasPoint = Qtrue;