B - N!

B - N!

Given an integer N(0 ≤ N ≤ 10000), your task is to calculate N!

Input One N in one line, process to the end of file.
Output For each N, output N! in one line.
Sample Input

1
2
3

Sample Output

1
2
6

hasNext()处理字符读入问题，和Next()效果其实是一样的，系统都会等待输入下一个字符，只是返回值不同，hasNext()会返回true，next()返回输入的字符。

import java.util.Scanner;
import java.math.BigInteger;
public class Main {
   public static void main(String args[]){
	   Scanner scan=new Scanner (System.in);
	   int n;
	   while(scan.hasNext()){
		   n=scan.nextInt();
		   BigInteger res=new BigInteger("1");//res初值为1
		   for(int i=1;i<=n;i++)
			    res=res.multiply(BigInteger.valueOf(i));//valuOf(i),将i转换为对应类型，在这个地方，i应该转化为大数类型
		   System.out.println(res);
	   }
   }
}