9.23
编程求N!
代码分析：
package lianxi;
import java.math.BigInteger;
import java.util.Scanner;
public class bo {
public static void main(String[] args) {
System.out.print("请输入N：");
Scanner scanner=new Scanner(System.in);
int number=scanner.nextInt();
System.out.println(number+"!="+calculateN2(number));
}
public static long calculateN(int n)
{
if(n==1 || n==0)
{
return 1;
}
return n*calculateN(n-1);
}
public static BigInteger calculateN2(int n)
{
if(n==1 || n==0)
{
return BigInteger.valueOf(1);
}
return BigInteger.valueOf(n).multiply(calculateN2((n-1)));
}
}
运行结果：
