2.3 周而复始的循环 知识点题库

Private Sub Command1_Click()

Dim x1 As Integer, x2 As Integer, n As Integer

Dim sum As Long

x1 = Val(Text1.Text)

x2 = Val(Text2.Text)

Sum = 0

If x1 < x2 Then n = 1 Else     

For i = x1 To x2 Step n

    If Then

        Sum = Sum + i

Next i

Label3.Caption = "从" & x1 & "到" & x2 & "之间所有奇数的累加和=" & Str(Sum)

End Sub

Private Sub Cmd1_Click()

    Dim s As String， c As String

    Dim flag As Boolean

    Dim i As Integer，count As Integer

    s=Text 1.Text

    flag=True

    For i=1 To Len(s) -1

        c=Mid(s，i，2)

        If c=“**”Then

            ①

            Exit For

        End If

    Next i

    s=“#”+s·“#”

    count =0：i= 2

    Do While flag And i<=Len(s) -1

        If ② Then

            s=Mid(s，1，i-1) +“*”+Mid(s， i+1， Len(s) -i)

            ③

        End If

        i=i+1

    Loop

    If Not flag Then

        Label2.Cnption=“警告！“

    Elself count = 0 Then

        Label2.Caption=“该排人数己满”

    Else

        Label2.Caption=“该排至多还能有”+Str(count) +“个人入座”

    End If

End Sub

① ② ③ 

Dim a(1 to 10) As Integer     ‘存储原始数据

Dim b(1 to 10)As Integer    ‘存放名次

Private Sub Command1_Click()

    Dim i As Integer, j As Integer, n As Integer

    For i=1 To 10 n=0

        For j=1 To 10

            If  Then

        Next j

    Next i

    b(i)= n

    For i= 1 to 10

        List2.Additem str(a(i))&“ ”&

    Next i

End Sub

Private Sub Form_Load()

‘随机产生 10 个[60,100]之间的随机数，并显示在 List1 中，代码略。

End Sub

Const N = 32 * 24

Dim a(1 To N) As Integer     'a 数组存储图像所有像素的灰度值

Private Sub Form_Load()

    '读取图像中的所有像素的灰度值存入a数组，代码略

End Sub

Private Sub Command1_Click()

    Dim i As Integer， j As Integer， k As Integer

    Dim sum As Long， sum1 As Long， N1 As Long， N2 As Long

    Dim μ1 As Double， μ2 As Double， diff As Double， max_var As Double

    Dim t1 As Integer， t2 As Integer， T As Integer

    Dim h(255) As Long

    Dim c(255) As Long

    max_var = 0: t1 = 0: t2 = 0: N1 = 0: N2 = 0: sum = 0: sum1 = 0

    For i = 0 To 255

        h(i) = 0: c(i) = 0

    Next i

    For i = 1 To N

        h(a(i)) = h(a(i)) + 1

    Next i

    c(0) = h(0)

    For i = 1 To 255

             '统计灰度值小于等于i 的像素个数

        sum = sum + i * h(i)

    Next i

    For k = 1 To 255

        N1 = c(k - 1)

        N2 = N - N1

        If N1 <> 0 And N2 <> 0 Then

            μ1 = sum1 / N1

            μ2 = (sum - sum1) / N2

            diff = N1 / N * N2 / N * (μ1 - μ2) ^ 2

            diff = Round(diff， 4)      'Round 函数的作用是对diff 保留四位小数

            If diff >= max_var Then

                t1 = k

            If diff > max_var Then

                max_var = diff

            End If

        End If

    Next k

    T = (t1 + t2) \ 2

    Label1.Caption = "将该图像分割为前景与背景两部分的最佳灰度值为：" & T

End Sub

import sys

def ishw(s)： #判断s是否是回文字符串

    if s==

         return True

    else：

       return False

s = input("请输入字符串： ")

n = len(s)

s=s+s

for i in range(n， 0， -1)： # 枚举字符串长度

    for j in

         t=s[j：j+i]

         if ishw(t)：

           print(“字符串环中的最长回文字符串是：”+ t)

           sys.exit(0) #提前结束程序

h=

s=input('触地前的发光颜色变化:') 

d={'R':0.8,'G':0.6,'B':0.5}

sum=h

for i in range(1,len(s)):

  h=d[c]*h

  sum=

print('弹球发光状态下的运动轨迹长度:'+str(sum))