'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
另外，dogfish也寫了一個求1000階乘的VBS：
復制代碼 代碼如下:
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 '把結果轉為字串。 str = "" for i=max_digit to ubound(digits) str = str & digits(i) next msgbox str
