uva : 568 - Just the Facts

#include<stdio.h>
int main()
{
    int  n;
    while(scanf("%d",&n)==1)
    {
        if(n==0)
           break;
        long num1[300000],lnum1=1,i,j,k,m,r=0,sum=0;
        num1[0]=1;
        for(i=2;i<=n;i++)
        {
            for(j=0;j<lnum1;j++)
            {
                m=(num1[j]*i+r)%10;
                r=(num1[j]*i+r)/10;
                num1[j]=m;
            }
            while(r!=0)
            {
                num1[lnum1++]=r%10;
                r=r/10;
            }
        }
        for(i=0;i<lnum1;i++)
        {
            if(num1[i]>0)
               break;
        }
        printf("%5d -> %d\n",n,num1[i]);
    }
    return 0;
}