Private Sub Command1_Click()
Dim a#, b#, c#, p#
Me.AutoRedraw = True
a = 3: b = 4: c = 5
Do
a = Val(InputBox("請輸入三角形第一條邊", "輸入", a))
b = Val(InputBox("請輸入三角形第二條邊", "輸入", b))
c = Val(InputBox("請輸入三角形第三條邊", "輸入", c))

If aa Then
p = (a + b + c) / 2 'S＝ √[p(p - a)(p - b)(p - c)] （海倫公式）（p=(a+b+c)/2））
Print "面積:"; (p * (p - a) * (p - b) * (p - c)) ^ 0.5
Exit Sub
Else
MsgBox "你輸入的數(shù)據(jù)構(gòu)成不了三角形!", vbQuestion + vbOKOnly, "請檢查輸入"
End If
Loop
End Sub