VB编程 利用InputBox输入三角形的三条边，计算其面积（用msgbox输出）。

Private Sub Form_Load()
Dim a, b, c As Single
Dim p , s As Single
a = Val(InputBox("请输入边长1"))
b = Val(InputBox("请输入另一边长"))
c = Val(InputBox("请输入最后一个边长"))
If a + b <= c Or a + c <= b Or b + c <= a Then
MsgBox ("不能构成三角形")
Else
p = (a + b + c) / 2
s = Sqr(p * (p - a) * (p - b) * (p - c))
MsgBox s
End If
End
End Sub