c语言求大数阶乘

大数的阶乘

#include

void main()

{

int a,b;

int i,j,k,n,carry,count;

unsigned long int result[500]={0};

do

{ a=0;

result[0]=1;

printf("qing shu ru yi ge zheng shu\n");

scanf("%d",&n);

if (n<0)

{

printf("qing chong xin shu ru yi ge zheng shu\n"); continue;}

else if(n==0)

{printf("%d!=%d\n",n,1);}

else

{

for(i=2;i<=n;++i)

{

for(j=0;j<=a;++j)

result[j]*=i;

for(k=0;k<=a;++k)

{

carry=result[k]/100000;

result[k]%=100000;

result[k+1]+=carry;

}

if(result[a+1]>0)

++a;

}

if(result[a]>=10000)

b=5;

else if(result[a]>=1000)

b=4;

else if(result[a]>=100)

b=3;

else if(result[a]>=10)

b=2;

else b=1;

printf("\n%d!=\n",n);

printf("%5d",result[a]);

result[a]=0;

count=1;

for(i=a-1;i>=0;--i )

{

printf("%05d",result[i]);

result[i]=0;

if(++count%10==0)

printf("\n");

}

if(a>=1)

printf("\ngong you %d wei\n",b+a*5) ;

else

printf("\ngong you %d wei\n",b);

printf("\n");

}

}

while(n!=0);

}

写了这么长的东西，把自己都绕迷了。高手几句话就概括了，每句浓缩的都是精华，这就是差距：

#include

int main(void)

{

long a[9000]={1,0},i,c,len,pos=1;

int n;

printf("请输入你要计算阶乘的数:\n");

scanf("%d",&n);

pos=n;

for ( len=1;n>1; n--)

{

for (c=0,i=0; i

{

a[i]=(c+=a[i]*n)%10000;

c/=10000;

}

((a[i]=c)>0)?len++:0;

}

printf("\n\n%d的阶乘:\n",pos);

for( len--,printf("%d",a[len--]);len>=0; len--) printf("%04d",a[len]);

printf("\n");

return 0;

}