用VBS精确计算100的阶乘的实现代码

 
function jx(x) 
j=1 
for i=2 to x 
j=j*i 
next 
jx=j 
end function 
msgbox jx(20) 

 
'Author: Demon 
'Website: http://demon.tw 
'Email: 380401911@qq.com 
Option Explicit 
Function multiple(byVal x, byVal y) 
Dim n, t, i, j, z, w() 
n = Len(x) - 1 
t = Len(y) - 1 
ReDim w(n + t + 1) 
x = CStr(x) : y = CStr(y) 
For i = 0 To UBound(w) 
w(i) = "0" 
Next 
For i = 0 To t 
Dim c : c = 0 
Dim uv : uv = 0 
For j = 0 To n 
uv = (w(i+j)-"0") + c + _ 
(Mid(x,n-j+1,1)-"0") * (Mid(y,t-i+1,1)-"0") 
w(i+j) = CStr(uv Mod 10 + "0") 
c = uv  10 
Next 
w(i+n+1) = CStr(uv  10 + "0") 
Next 
z = Join(w,"") 
z = StrReverse(z) 
Do While Left(z,1) = "0" 
z = Mid(z,2) 
Loop 
multiple = z 
End Function 
Function factorial(n) 
Dim i, t : t = 1 
For i = 1 To n 
t = multiple(t, i) 
Next 
factorial = t 
End Function 
Dim t : t = Timer 
WScript.Echo factorial(100) 
WScript.Echo Timer - t 

 
dim digits(2568) 
max_digit = 2568 
digits(max_digit) = 1 
for d=2 to 1000 
for k=max_digit to ubound(digits) 
digits(k) = digits(k) *d 
next 
k = ubound(digits) 
while k>=max_digit 
if digits(k)>10 then 
digits(k-1) = digits(k-1) + fix(digits(k) / 10) 
digits(k) = digits(k) mod 10 
if k-1<max_digit then 
max_digit = k - 1 
end if 
end if 
k = k-1 
wend 
next 
'把结果转为字串。 
str = "" 
for i=max_digit to ubound(digits) 
str = str & digits(i) 
next 
msgbox str