//下面是求10000的阶乘
#include    <stdio.h>
typedef struct BigNum_
{
    int data[10000];
    int n;
} BigNum;
BigNum*    carry(BigNum* bn, int curr, int valid, int inc)
{
    return curr>=valid && inc ? (++bn->n,
        bn->data[curr] = inc%10000, carry(bn, curr+1, valid, inc/10000)) : bn;
}
BigNum* mul(BigNum* bn, int n, int curr, int valid, int inc)
{
    int t = inc+bn->data[curr]*n;
    return curr >= valid ?
        carry(bn, curr, valid, inc) :
    (bn->data[curr]=t%10000, mul(bn, n, curr+1, valid, t/10000));
}
BigNum* power(BigNum* bn, int n, int p)
{
    return --p ? (power(bn, n, p), mul(bn, n, 0, bn->n, 0)) : 
    (bn->n=1, bn->data[0] = n, bn);
}
BigNum* fac(BigNum* bn, int n)
{
    return n ? (fac(bn, n-1), mul(bn, n, 0, bn->n, 0)): (bn->n=1, bn->data[0] = 1, bn);
}
void show(BigNum* bn, int curr)
{
    if (curr != bn->n)
    {
        show(bn, curr+1);
        curr == bn->n -1 ? printf("%d", bn->data[curr]) : 
        printf("%04d", bn->data[curr]);
        !curr ? puts("") : 0;
    }
}

BigNum n;
int main(int argc, char* argv[]) 
{ 
    show(fac(&n, 10000), 0);
    return 0; 
} 

compute 1000!
comput time: 6562 ms
Result = 4023872600770937735437024339230
0398571937486421071463254379991042993851
2398629020592044208486969404800479988610
1971960586316668729948085589013238296699
4459099742450408707375991882362772718873
2519779505950995276120874975462497043601
4182780946464962910563938874378864873371
1918104582578364784997701247663288983595
5735432513185323958463075557409114262417
4743493475534286465766116677973966688202
9120737914385371958824980812686783837455
9731746136085379534524221586593201928090
8782973084313928444032812315586110369768
0135730421616874760967587134831202547858
9320767169132448426236131412508780208000
2616831510273418279777047846358681701643
6502415369139828126481021309276124489635
9928705114964975419909342221566832572080
8213331861168115536158365469840467089756
0290095053761647584772842188967964624494
5160765353408198901385442487984959953319
1017233555566021394503997362807501378376
1530712776192684903435262520001588853514
7331611702103968175921510907788019393178
1141945452572238655414610628921879602238
3897147608850627686296714667469756291123
4082439208160153780889893964518263243671
6167621791689097799119037540312746222899
8800519544441428201218736174599264295658
1746628302955570299024324153181617210465
8320367869061172601587835207515162842255
4026517048330422614397428693306169089796
8482590125458327168226458066526769958652
6822728070757813918581788896522081643483
4482599326604336766017699961283186078838
6150279465955131156552036093988180612138
5586003014356945272242063446317974605946
8257310379008402443243846565724501440282
1885252470935190620929023136493273497565
5139587205596542287497740114133469627154
2284586237738753823048386568897646192738
3814900140767310446640259899490222221765
9043399018860185665264850617997023561938
9701786004081188972991831102117122984590
1641921068884387121855646124960798722908
5192968193723886426148396573822911231250
2418664935314397013742853192664987533721
8940694281434118520158014123344828015051
3996942901534830776445690990731524332782
8826986460278986432113908350621709500259
7389863554277196742822248757586765752344
2202075736305694988250879689281627538488
6339690995982628095612145099487170124451
6461260379029309120889086942028510640182
1543994571568059418727489980942547421735
8240106367740459574178516082923013535808
1840096996372524230560855903700624271243
4169090041536901059339838357779394109700
2775347200000000000000000000000000000000
0000000000000000000000000000000000000000
0000000000000000000000000000000000000000
0000000000000000000000000000000000000000
0000000000000000000000000000000000000000
0000000000000000000000000000000000000000
00000000000000000
output time: 500 ms
请按任意键继续. . .

#include <algorithm>
#include <vector>
#include <cstdio>
#include<functional>
#include<time.h>

typedef  unsigned int Type;
enum { BASE_DATA = 10000, MAX_NUM = 1000 , MAX_SIZE = MAX_NUM+1000};
struct ConverData
{
    inline Type operator()(Type x)
        {
            Type y = (x/1000);
            x %= 1000;
            y += ( x/ 100)<<8;
            x %= 100;
            y += ( x / 10)<<16;
            y += (x % 10)<<24;
            return y + 0x30303030 ;
        }
};
int main(int , char* [])
{
    clock_t start = clock();

    std::vector<Type> v;
    v.reserve(MAX_SIZE);
    v.push_back(1);
    v.push_back(0);
    for(int x= 2 ; x < MAX_NUM +1 ; ++ x)
    {
        std::transform(v.begin() ,v.end(),v.begin(),std::bind2nd(std::multiplies<Type>(),x));
        std::vector<Type>::iterator i = v.begin();
        for(; i+1!=v.end();++i){
            *(i+1) += (*i)/BASE_DATA ;
            (*i) %= BASE_DATA;
        }
        if( *i >= BASE_DATA ){
            Type temp = (*i)/BASE_DATA ;
            (*i) %= BASE_DATA;
            v.push_back( temp );
        }
    }
    std::reverse(v.begin() ,v.end() );
    v.erase( v.begin()  , std::find_if( v.begin() ,v.end()  , std::bind2nd(std::not_equal_to<Type>(),0) ) );//移除结果开头的0
    std::transform( v.begin() ,v.end() , v.begin() , ConverData() );//转化成字符串
    v.push_back(0);
    std::printf("%s\n",&v[0]);
    std::printf("%d\n",clock()-start);
    return 0;
}

#include <algorithm>
#include <vector>
#include <cstdio>
#include<functional>
#include<time.h>
#include<windows.h>