Java求大整数的阶乘代码

Java求大整数的阶乘代码

代码转自：http://blog.sina.com.cn/s/blog_64ca6cfb0100u1aq.html

import java.io.*;
public class jiecheng {
    public static void main(String args[]) throws IOException{
        int Data[]=new int[80];
        int Digit;
        int i,j,r,k;
        int N;
        for(i=1;i<40;i++)
            Data[i]=0;
        Data[0]=1;
        Data[1]=1;
        Digit=1;
        System.out.println("Enter a number what you want to calculus:");
        BufferedReader dr=new BufferedReader(new InputStreamReader(System.in));
        N=Integer.parseInt(dr.readLine());
        for(i=1;i<N+1;i++)
        {
            for(j=1;j<Digit+1;j++)
            {
                Data[j]*=i;
            }
            for(j=1;j<Digit+1;j++)
            {
                if(Data[j]>10)
                {
                    for(r=1;r<Digit+1;r++)
                    {
                        if(Data[Digit]>10)
                        {
                            Digit++;
                        }
                        Data[r+1]+=Data[r]/10;
                        Data[r]=Data[r];
                    }
                }
            }
            System.out.print(i+"!= ");
            for(k=Digit;k>0;k--)
            {
                System.out.print(Data[k]);
            }
            System.out.println("");
        }
    }
}