题型:单选题 题类:常考题 难易度:普通
教科版高中信息技术选修一 对分查找变式
Private Sub Command1_Click( )
Dim L As Integer, R As Integer,n As Integer
x As Integer
n=Val(Text1.Text)
L=1
R=n+1
Do While
x=(L+R)\2
if 2^X+3*x-5<=n Then L=x+1
Else R=x-1
Loop
Label1.Cption=“方程2^X+3*x-5<=n的最大正整数解为:”+
End Sub
要使程序实现上述算法思想,则方框上的语句是( )
i= 1 : j =9 : n =0
key=Val( Textl.Text)
Do While i <= j
m=(i + j) \ 2
If key = d(m) Then
Exit Do
j= m - 1
Else
i=m+1
End If
Loop
方框中的正确代码应为( )
a(1) |
a(2) |
a(3) |
…… |
a(n —2) |
a(n—1) |
a(n) |
3 |
25 |
38 |
…… |
55 |
31 |
12 |
依据对分查找思想,设计一个在数组a中查找数据key的程序。实现该功能的VB程序如下,但加框处代码有错,请改正。
Private Sub Command1_Click()
Const n = 6
Dim a(1 To n)As Integer,flag As Boolean
Dim i As Integer,j As Integer,m As Integer,key As Integer
'读取一组正整数,按上述规则存入数组a中,代码略。
key = VaKText1. Text)
i = 1
j = (n + 1) \ 2
flag = False
Do While And Not flag ‘①
m = (i + j) \ 2
If key = a(m) Then
flag = True
ElseIf key< a(m) Then
j = m - 1
Else
i = m + 1
End If
Loop
If Not flag And j > 0 Then
m = ‘②
If key = a(m) Then flag = True
End If
If flag Then
Text2. Text = Str(m)
Else
Text2. Text = "找不到"
End If
End Sub
①{#blank#}1{#/blank#} ②{#blank#}2{#/blank#}
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