13.有如下Visual Basic自定義函數(shù): Function f(i As Single) As Boolean If i<=0Then f=True Else f=False End Function 執(zhí)行語(yǔ)句s=f(-0.4)后,邏輯型變量s的值是( ?。?/h2>
14.有如下的Visual Basic程序: Private Sub Command1_Click( ?。?br />Const pi=3.14 Dim s As Single,r As Single r=Val(text1.Text) pi=3.1415 s=pi*r^2 Label1.Caption=“面積為“+Str(s) End Sub 程序運(yùn)行后,單擊命令按鈕Command1,出現(xiàn)如圖所示的錯(cuò)誤提示,下列原因分析正確的是( ?。?nbsp;