Private Sub Form_Load()
Do
Dim a As Single,b As Single,c As Single,p As Single,s As Single
a = Val(InputBox("请输入三角形第1条边长"))
b = Val(InputBox("请输入三角形第2条边长"))
c = Val(InputBox("请输入三角形第3条边长"))
s = (a + b + c) / 2
If a >= s Or b >= s Or c >= s Then
MsgBox "不能构成三角形"
Else
area = Sqr(s * (s - a) * (s - b) * (s - c))
MsgBox "面积为" & area
End If
Loop
End
End Sub