九度OJ题目1076：N的阶乘 (java)运用BigInteger的例子。

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 1 package a;
 2 import java.math.BigInteger;
 3 import java.util.*;
 4 public class Main{
 5     public static  void main(String[] args)  {
 6         Scanner cin = new Scanner(System.in);
 7         while(cin.hasNext()){
 8             BigInteger b1;
 9             BigInteger b2=BigInteger.ONE;
10             BigInteger b3=BigInteger.ONE;
11             b1=cin.nextBigInteger();
12             while(b1.compareTo(BigInteger.ZERO)>0)
13             {
14                 b2=b2.multiply(b1);
15                 b1=b1.subtract(b3);
16             }
17             System.out.println(b2.toString());
18      }
19         cin.close();
20     }
21 }