func zeroFill(prefix string, width int, suffix string) string {
	return prefix + strings.Repeat("0", width-len(suffix)) + suffix
}

func TestSprintf(t *testing.T) {
	for _, tt := range fmtTests {
		s := Sprintf(tt.fmt, tt.val)
		i := strings.Index(tt.out, "PTR")
		if i >= 0 && i < len(s) {
			var pattern, chars string
			switch {