diff --git a/iter_object.go b/iter_object.go
index 58ee89c..0abd881 100644
--- a/iter_object.go
+++ b/iter_object.go
@@ -40,7 +40,7 @@ func (iter *Iterator) ReadObject() (ret string) {
 	case '}':
 		return "" // end of object
 	default:
-		iter.ReportError("ReadObject", fmt.Sprintf(`expect { or , or } or n, but found %s`, string([]byte{c})))
+		iter.ReportError("ReadObject", fmt.Sprintf(`expect { or , or } or n, but found %c`, c))
 		return
 	}
 }
diff --git a/iter_skip.go b/iter_skip.go
index e91eefb..cf64c97 100644
--- a/iter_skip.go
+++ b/iter_skip.go
@@ -97,34 +97,34 @@ func (iter *Iterator) Skip() {
 
 func (iter *Iterator) skipFourBytes(b1, b2, b3, b4 byte) {
 	if iter.readByte() != b1 {
-		iter.ReportError("skipFourBytes", fmt.Sprintf("expect %s", string([]byte{b1, b2, b3, b4})))
+		iter.ReportError("skipFourBytes", fmt.Sprintf("expect %s", []byte{b1, b2, b3, b4}))
 		return
 	}
 	if iter.readByte() != b2 {
-		iter.ReportError("skipFourBytes", fmt.Sprintf("expect %s", string([]byte{b1, b2, b3, b4})))
+		iter.ReportError("skipFourBytes", fmt.Sprintf("expect %s", []byte{b1, b2, b3, b4}))
 		return
 	}
 	if iter.readByte() != b3 {
-		iter.ReportError("skipFourBytes", fmt.Sprintf("expect %s", string([]byte{b1, b2, b3, b4})))
+		iter.ReportError("skipFourBytes", fmt.Sprintf("expect %s", []byte{b1, b2, b3, b4}))
 		return
 	}
 	if iter.readByte() != b4 {
-		iter.ReportError("skipFourBytes", fmt.Sprintf("expect %s", string([]byte{b1, b2, b3, b4})))
+		iter.ReportError("skipFourBytes", fmt.Sprintf("expect %s", []byte{b1, b2, b3, b4}))
 		return
 	}
 }
 
 func (iter *Iterator) skipThreeBytes(b1, b2, b3 byte) {
 	if iter.readByte() != b1 {
-		iter.ReportError("skipThreeBytes", fmt.Sprintf("expect %s", string([]byte{b1, b2, b3})))
+		iter.ReportError("skipThreeBytes", fmt.Sprintf("expect %s", []byte{b1, b2, b3}))
 		return
 	}
 	if iter.readByte() != b2 {
-		iter.ReportError("skipThreeBytes", fmt.Sprintf("expect %s", string([]byte{b1, b2, b3})))
+		iter.ReportError("skipThreeBytes", fmt.Sprintf("expect %s", []byte{b1, b2, b3}))
 		return
 	}
 	if iter.readByte() != b3 {
-		iter.ReportError("skipThreeBytes", fmt.Sprintf("expect %s", string([]byte{b1, b2, b3})))
+		iter.ReportError("skipThreeBytes", fmt.Sprintf("expect %s", []byte{b1, b2, b3}))
 		return
 	}
 }