随机字符在asp中用途很多,比如给上传的图片文件命名,登陆验证码,还有文章类网站的干扰码等等,下面列举了8个常用的随机字符的函数.
1.
function MyRandc(n)
‘生成随机字符，n为字符的个数 ，该随机函数由大小写字母组成，不含数字
dim thechr
thechr = ""
for i=1 to n
dim zNum,zNum2
Randomize
zNum = cint(25*Rnd)
zNum2 = cint(10*Rnd)
if zNum2 mod 2 = 0 then
zNum = zNum + 97
else
zNum = zNum + 65
end if
thechr = thechr & chr(zNum)
next
MyRandc = thechr
end function
function gen_key(digits)
'定义并初始化数组
dim char_array(80)
'初始化数字
for i = 0 to 9
char_array(i) = cstr(i)
next
'初始化大写字母
for i = 10 to 35
char_array(i) = chr(i + 55)
next
'初始化小写字母
for i = 36 to 61
char_array(i) = chr(i + 61)
next
randomize '初始化随机数生成器。
do while len(output) < digits
num = char_array(int((61 - 0 + 1) * rnd + 0))
output = output + num
loop
'设置返回值
gen_key = output
end function使用方法：
把结果返回给浏览器
response.write "本实例生成的十三位随机字符串为:"
response.write "<center>"
response.write gen_key(13)'这里可以更改长度
response.write "</center>"
dim a(5)
randomize
t=int(rnd*5)
a(0)="yingyu"
a(1)="laoda"
a(2)="wangzhan"
a(3)="maiwangzhan"
a(4)="hehe"
public function Generate_Key()
Randomize
do
num = Int((75 * Rnd)+48)
found = false
if num >= 58 and num <= 64 then
found = true
else
if num >=91 and num <=96 then
found = true
end if
end if
if found = false then
RSKey = RSKey+Chr(num)
end if
loop until len(RSKey)=16
Generate_Key=RSKey
end function
function makePassword(byVal maxLen)
Dim strNewPass
Dim whatsNext, upper, lower, intCounter
Randomize
For intCounter = 1 To maxLen
whatsNext = Int((1 - 0 + 1) * Rnd + 0)
If whatsNext = 0 Then
upper = 90
lower = 65
Else
upper = 57
lower = 48
End If
strNewPass = strNewPass & Chr(Int((upper - lower + 1) * Rnd + lower))
Next
makePassword = strNewPass
end function使用方法：dim radpass
response.write makePassword(6) '6位字符
Function rndNum (strLong)
Dim temNum
Randomize
Do While Len(RndNum) < strLong
temNum=CStr(Chr((57-48)*rnd+48))
RndNum=RndNum&temNum
loop
End Function
Function rndNumber(iLessCount,iMostCount,iLessNumber,iMostNumber,cutZero)
If iLessCount = 0 OR iMostCount < iLessCount OR NOT _
isnumeric(iLessCount) OR NOT isnumeric(iMostCount) OR NOT _
isnumeric(iLessNumber) OR NOT isnumeric(iMostNumber) _
OR (iLessNumber = iMostNumber) Then Exit Function
'最少个数零、最大个数小于最小个数、4个参数不为数字、最小数等于最大数就退出函数
Randomize
Dim iRnd,sZero
Dim sOutput
Dim iLength
Dim sTempOutput
Dim i
Dim iCount
iCount = int(rnd*(iMostCount-iLessCount+1))+iLessCount’计算随机取几个数
iLength = len(iMostNumber)*iCount+(iCount*2)
'长度为最大数长度乘以随机个数加上随机个数乘以2（每个数前后各一个逗号，用来全字匹配）
Do While len(sOutput) < iLength'输出小于长度时循环
iRnd = int(rnd*(iMostNumber-iLessNumber+1))+iLessNumber'取随机数
If Len(iRnd) < len(iMostNumber) Then'随机数长度小于取最大数长度
For i = 1 To len(iMostNumber) - len(iRnd)'那么就要在首位加缺少的零
sZero = sZero & "0"
Next
End If
iRnd = sZero & iRnd'把零加在随机数前面
sZero = empty'清空首位零，循环后还要调用
If Instr(sOutput,","&iRnd&",") < 1 Then'不在输出变量中就放进去0
sOutput = sOutput & "," & iRnd & ","
End If
Loop
sOutput = mid(sOutput,2,len(sOutput)-2)'去掉首尾逗号
sOutput = Replace(sOutput,",,",",")'把双逗号替换成单逗号
If cutZero = true Then'如果要去除首位多余的零
sTempOutput = split(sOutput,",")'拆分为数组
sOutput = empty'清空，后面要重新放入
For i = 0 To Ubound(sTempOutput)'逐个转换成数值后放入
sOutput = sOutput & Clng(sTempOutput(i)) & ","
Next
sOutput = mid(sOutput,1,len(sOutput)-1)'去掉末尾逗号
End If
rndNumber = sOutput'输出
End Function
function rndcode(byVal stars,byVal ends)
from:aspxhome.com
dim rndlen,i
randomize
rndLen = int(stars*rnd+ends-stars)
for i = 1 to rndLen
randomize
rndcode = rndcode & chr(int(127*rnd+1))
next
end function
