package com.melon.apk.util;

import java.math.BigInteger;

/**
 * 阶乘
 * n!定义：1x2x3...x(n-1)xn
 * 即小于等于它的所有数相乘
 */
public class Factorial {

    /**
     * 计算n的阶乘
     *
     * @param n 代表N!
     */
    private static void calc(int n) {
        BigInteger sum = BigInteger.valueOf(1);
        for (int i = 1; i <= n; i++) {
            sum = sum.multiply(BigInteger.valueOf(i));
        }

        System.out.println(n+"的阶乘为:");
        System.out.println(sum);
    }

    public static void main(String[] args) {
        calc(100);
    }
}