用VBS精确计算2的100次方的代码

既然python可以计算2的100次方，那么我就要用vbs实现。不过这个效率嘛，计算2的10000次方python用了0.009013秒，vbs用了120.9805秒，不是一个等级的，我就不多说什么了。

直接上代码：

'date: 2010/10/27
'author: demon
'qq: 380401911
'e-mail: [e-mail]

begin = timer
n = 1
for i = 1 to 100
n = multiple(n, 2)
next
finish = timer
wscript.echo n
wscript.echo finish - begin

'grade school multiplication, algorithm 14.12
'http://www.cacr.math.uwaterloo.ca/hac/about/chap14.pdf
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

原文：http://demon.tw/programming/vbs-long-multiplication.html