第5章VB循环结构For

1、125.3 5.3 循循 环环 结结 构构 n =val(inputbox(输入数据输入数据) select case n case 1, 3, 5, 7, 9 print n; 是奇数。是奇数。 case 0, 2, 4, 6, 8 print n; 是偶数。是偶数。 case else print n; 超出范围！超出范围！ end selectn = val(inputbox(输入数据输入数据)select case n case 1, 3, 5, 7, 9 print n; 是奇数。是奇数。 case 0, 2, 4, 6, 8 print n; 是偶数。是偶数。 case else

2、print n; 超出范围！超出范围！end selectfor k=1 to 10 next k3计数循环语句计数循环语句 for-nextfor-next条件循环语句条件循环语句 while-wend while-wend do-loop do-loop4( (一般用于循环次数已知一般用于循环次数已知) )56) 1(步长初值终值int0 初值终值 ( 终值=0 死循环7p50例题private sub form_click() dim s as single, i as integer n = val(inputbox(请输入请输入n, 提示提示) s = 0 for i = 1 to

3、n step 1 s = s + i next i print 1到到; n; 之和为：之和为：; send sub8ny结束结束91011private sub form_click( ) sum=0 for next end sub 12private sub form_click() n = val(inputbox(输入输入n=) s= 1 for k= ? to ? step ? ?=? next ?end sub13思路：思路：1.1.输入一个分数，判断是否有效并进行处理；输入一个分数，判断是否有效并进行处理；2.2.判断是否合格，计算合格的人数；判断是否合格，计算合格的人数；3.

4、3.计算总人数、总分数和平均分。计算总人数、总分数和平均分。14例例: :改变循环控制变量对循环的影响改变循环控制变量对循环的影响private sub command1_click() j = 0 for i = 1 to 20 step 2 i = i + 3 j = j + 1 print 第; j; 次循环i=; i next i print 退出循环后i=; i end sub正常情况：i=1,3,5,7,9,11,13,15,17,19现在：i=4,9,14,1915 private sub command1_click() s = 0 for k = 1 to 3 if k =

5、1 then x = 1 elseif k = 2 then x = 2 elseif k = 3 then x = 3 else x = 4 end if s = s + x next k print s end sub16private sub form_click( ) dim n as integer dim sum as integer sum=0 for n=1 to 5 step 1 sum=sum+n next n end sub 17private sub form_click( ) dim n as integer dim p as integer p=1 for n=3

6、to 7 step 1 if n mod 2=0 then p=p*n end if next n end sub 18private sub form_click( ) dim str1 as string dim letter as integer dim number as integer dim other as integer dim n as integer letter=0: number=0: other=0 str1=inputbox(“输入字符串输入字符串=”,”输入框输入框”,”ab32-c,4d_5”) for n=1 to len(str1) select case mid(str1,n,1) case “a” to “z”, “a” to “z” letter=letter+1 c