【正确答案】[解析] 程序中用到了RGB函数，该函数通过红、绿、蓝三基色产生某种颜色，语法为RGB(红，绿，蓝)函数，其中括号中的红、绿、蓝三基色的范围为0～255之间的整数。解题步骤：
第一步：编写程序代码。
程序提供的代码：
Option Explicit
Private Sub Command1_Click()
End
End Sub
Private Sub Form_Load()
'Label4.BackColor = RGB( ?, HScroll2.Value, HScroll3.Value)
End Sub
Private Sub HScroll1_Change()
'Label4.? = RGB(HScrolll.Value, HScroll2.Value, HScroll3.Value)
End Sub
Private Sub HScroll2_Change()
'Label4.BackColor = ?(HScroll1.Value, HScroll2.Value, HScroll3.Value)
End Sub
Private Sub HScroll3_Change()
'? = RGB(HScrolll.Value, HScroll2.Value, HScroll3.Value)
End Sub
参考代码：
Option Explicit
Private Sub Command1_Click()
End
End Sub
Private Sub Form_Load()
Label4.BackColor = RGB(HScroll1.Value, HScroll2.Value, HScroll3.Value)
End Sub
Private Sub HScroll1_Change()
Label4.BackColor = RGB(HScrolll.Value, HScroll2.Value, HScroll3.Value)
End Sub
Private Sub HScroll2_Change()
Label4.BackColor = RGB(HScroll1.Value, HScroll2.Value, HScroll3.Value)
End Sub
Private Sub HScroll3_Change()
Label4.BackColor = RGB(HScrolll.Value, HScroll2.Value, HScroll3.Value)
End Sub
第二步：调试并运行程序。
第三步：按题目要求存盘。
(2)[解析] 该题用到两个函数和一个公式，Val()是将其内容转变为数字类型，Sqr()是求数值的平方根，而求解三角形的面积的时候用到海伦公式即S=Sqr(p*(p-a)*(p-b)*(p-c))，其中a、b、c是三角形的三个边，p=(a+b+c)/2。
解题步骤：
第一步：编写程序代码。
程序提供的代码：
Option Explicit
Dim a As Single
Dim b As Single
Dim c As Single
Dim S As Double
Dim L As Single
Private Sub Command1_Click()
a = Val (Text5.Text)
b = Val (Text6.Text)
c = Val (Text7.Text)
'If ? Then
Textl.Text = "是三角形"
'If ? Then
Text2.Text = "是直角三角形"
Else
'If ? Then
Text2.Text = "是锐角三角形"
Else: Text2.Text = "是钝角三角形"
End If
End If
Text3.Text = a + b + c '计算三角形的周长
L = (a + b + c) / 2
Text4.Text = Sqr(L * (n - a) * (L - b)(L - c) ) '计算三角形的面积
Else: Text1.Text = "非三角形"
Text2.Text = ""
Text3.Text = ""
Text4.Text = ""
End If
Command2.Enabled = True
End Sub
Private Sub Command2_Click ()
'此处需要设置，以实现清空所有文本框及使“清除再来”失效的功能
'?
End Sub
Private Sub Command3_Click()
End
End Sub
Private Sub Form_Load ()
Text1.Enabled = False
Text2.Enabled = False
Text3.Enabled = False
Text4.Enabled = False
Command2.Enabled = False
End Sub
参考代码:
Option Explicit
Dim a As Single
Dim b As Single
Dim c As Single
Dim S As Double
Dim L As Single
Private Sub Command1_Click()
a = Val (Text5.Text)
b = Val(Text6.Text)
c = Val (Text7.Text)
If a ＜＞ 0 And b ＜＞ 0 And c ＜＞ 0 And a + b ＞ c And a + c ＞ b And b + c ＞ a Then
Text1.Text = "是三角形"
If a ^ 2 + b ^ 2 = c ^ 2 Or a ^ 2 + c ^ 2 = b ^ 2 Or b ^ 2 + c ^ 2 = a ^ 2 Then
Text2.Text = "是直角三角形"
Else
If a ^ 2 +b ^ 2 ＞ c ^ 2Anda ^ 2 + c ^ 2 ＞ b ^ 2 And b ^ 2 + c ^ 2 ＞ a ^ 2 Then
Text2.Text = "是锐角三角形"
Else: Text2.Text = "是钝角三角形"
End If
End If
Text3.Text = a + b + c
L = (a + b + c) / 2
Text4.Text = Sqr(L * (L - a) * (L - b) * (L - c) )
Else
Text1.Text = "非三角形"
Text2.Text = ""
Text3.Text = ""
Text4.Text = ""
End If
Command2.Enabled = True
End Sub
Private Sub Command2_Click()
Text1.Text = ""
Text2.Text = ""
Text3.Text = ""
Text4.Text = ""
Text5.Text = ""
Text6.Text = ""
Text7.Text = ""
Command2.Enabled = False
End Sub
Private Sub Command3_Click()
End
End Sub
Private Sub Form_Load()
Text1.Enabled = False
Text2.Enabled = False
Text3.Enabled = False
Text4.Enabled = False
Command2.Enabled = False
End Sub
第二步：调试并运行程序。
第三步：按题目要求存盘。