设计一程序用二分法解方程x*x+4x-4=0
2个回答
vb吧
Private Sub Command1_Click()
'定义一些变量 很简单 学过数学都懂.
Dim a As Single,b As Single
Dim c As Single,d As Single
Dim ds As Single
Dim x1,x2 As String
a = Val(Text1.Text)
b = Val(Text2.Text)
c = Val(Text3.Text)
d = b * b - 4 * a * c
ds = Sqr(Abs(d))
'下面是程序段将用到选择语句的嵌套.
If d > 0 Then
x1 = Str((-b + ds) / (2 * a))
x2 = Str((-b - ds) / (2 * a))
Else
If d = 0 Then
x1 = Str(-b / (2 * a)):x2 = x1
Else
b = Round(-b / (2 * a),7):c = Round(ds / (2 * a),7)
x1 = Str(b) + "+" + Str(c) + "i"
x2 = Str(b) + "-" + Str(c) + "i"
End If
End If
Text4.Text = x1:Text5.Text = x2 '使用文本框输出两个根
End Sub
Private Sub Form_Activate()
Text1.SetFocus '程序开始焦点放在text内 方便 习惯
End Su
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