\(0 \le N \le 1000\),求\(N!\),考察高精度乘法。
const int N=3010;
struct bignum
{
int m[N];
int len;
bignum()
{
memset(m,0,sizeof m);
len=0;
}
};
int n;
bignum mul(bignum a,int b)
{
bignum c;
c.len=a.len;
int carry=0;
for(int i=0;i<c.len;i++)
{
int t=a.m[i]*b+carry;
c.m[i]=t%10;
carry=t/10;
}
while(carry)
{
c.m[c.len++]=carry%10;
carry/=10;
}
return c;
}
int main()
{
while(cin>>n)
{
bignum a;
a.m[a.len++]=1;
for(int i=1;i<=n;i++) a=mul(a,i);
for(int i=a.len-1;i>=0;i--) cout<<a.m[i];
cout<<endl;
}
//system("pause");
return 0;
}