Scanner的使用

package com.self.demo;

import java.util.Scanner;

public class Demo5 {

    public static void main(String[] args) throws Exception {

        System.out.println(f(5));
        boolean flag = true;

        do {
            Scanner scanner = new Scanner(System.in);

            System.out.println("请输入");

            int i = 0;
            String a = null;

            while (scanner.hasNextInt()) {
                i = scanner.nextInt();
                if (f2(i) == 0) {
                    System.out.println("请重新输入");
                    break;

                } else {
                    System.out.println(i + "的阶乘是:" + f2(i));
                }
                if (i == 0) {
                    scanner.close();
                    flag = false;
                    break;

                }

            }
            while (scanner.hasNext()) {
                a = scanner.next();
                if ("close".equals(a)) {
                    scanner.close();
                    flag = false;
                    break;

                } else {
                    break;
                }
            }

        } while (flag);

    }

    public static int f2(int i) {

        if (i == 1) {
            return 1;
        } else if (1 < i) {
            return (i * f2(i - 1));
        } else {
            return 0;
        }

    }

    public static int f(int i) {

        int result = 1;
        for (int k = 1; k <= i; k++) {

            result = k * result;

        }
        return result;

    }

}