import java.util.*;
import java.math.*;
public class Main {
public static void main(String[] args) {
// TODO Auto-generated method stub
Scanner in=new Scanner(System.in);
while(in.hasNext())
{
BigInteger sum=BigInteger.valueOf(1);
int n=in.nextInt();
for(int i=1;i<=n;i++)
{
sum=sum.multiply(BigInteger.valueOf(i));
}
System.out.println(sum);
}
}
}
BigInteger.valueOf(i):将i转换为BigInteger类型
在数值上:
sum.multiply(BigInteger.valueOf(i))=sum*i