s = Text1.Text

For i = 1 To Len(s) c = Mid(s, i, 1)

s1 = s1 + c Next i Text2.Text = s1

程序运行时，在文本框Text1中输入“ABC123xyz”，在文本框Text2中输出“bcd123yza”，则加框①处的代码为（ ）

A.

Private Sub Command1_Click()

    Dim As Single, b As Single, c As Single, p As Single, s As Single

    a≡Val(Text1. Text)

    b=Val(Text2. Text)

    c=Val(Text3. Text)

    p=(a+b+c)/2

    If a＜=p Or b＞=p Or c＞=p Then

        Label1. Caption="不能构成三角形"

    Else

        s=Sqr(p*(p-a)*(p-b)*(p-c))*p

        Label1. Caption="面积为"& s

    End If

End Sub

def bin(n):

    if n==0:

        return

    else:

        bin(n//2)

    print(n%2,end='')

bin(13)