java第十周作业
课堂练习:两个数求平方和
public class MyMethod { public static int sum(int a, int b) { return a * a + b * b; } public static void main(String[] args) { System.out.println(sum(4, 5)); } }
1.编写一个方法,实现冒泡排序(由小到大),并调用该方法
package homework; import java.util.Scanner; public class HM1 { public static void mppx() { Scanner input = new Scanner(System.in); System.out.println("请输入5个数:"); int x[] = new int[5]; for (int i = 0; i < x.length; i++) { x[i] = input.nextInt(); } for (int i = 0; i < x.length - 1; i++) { for (int j = 0; j < x.length - 1 - i; j++) { if (x[j] > x[j + 1]) { int temp = x[j]; x[j] = x[j + 1]; x[j + 1] = temp; } } } System.out.println("---------排序----------"); for (int i = 0; i < x.length; i++) { System.out.println(x[i]); } } public static void main(String[] args) { mppx(); } }
2.编写一个方法,求整数n的阶乘,例如5的阶乘是1*2*3*4*5。 [必做题]
package homework; public class HM2 { public static int jc(int x) { int sum = 1; for (int i = 1; i <= x; i++) { sum *= i; } return sum; } public static void main(String[] args) { System.out.println(jc(5)); } }
3.编写一个方法,判断该年份是平年还是闰年。[必做题]
package homework; import java.util.Scanner; public class HM3 { public static void pdnf() { Scanner input = new Scanner(System.in); System.out.println("请输入年份"); int year = input.nextInt(); if (year % 4 == 0 && year % 100 != 0 || year % 400 == 0) { System.out.println("该年份是闰年"); } else { System.out.println("该年份是平年"); } } public static void main(String[] args) { pdnf(); } }
4.课堂没完成的menu菜单,实现幸运抽奖功能
package homework; import java.util.Random; import java.util.Scanner; public class Menu { public static void mainMenu() { Scanner input = new Scanner(System.in); System.out.println("欢迎使用本系统"); System.out.println("1.登录"); System.out.println("2.注册"); System.out.println("3.幸运抽奖"); System.out.println("4.退出系统"); System.out.println("请选择:"); int i = input.nextInt(); switch (i) { case 1: login(); break; case 2: register(); break; case 3: draw(); break; } } public static void draw() { Scanner input = new Scanner(System.in); System.out.println("输入一个4位会员卡号"); int number = input.nextInt(); int baiwei = number / 100 % 10; Random r = new Random(); int a = (int) r.nextInt(10); if (baiwei == a) { System.out.println("该用户是幸运会员"); } else { System.out.println("该用户不是幸运会员"); } returnMain(); } public static void register() { Scanner input = new Scanner(System.in); System.out.println("输入用户名"); String uname = input.next(); System.out.println("输入密码"); String pwd = input.next(); System.out.println("注册成功"); returnMain(); } public static void returnMain() { Scanner input = new Scanner(System.in); System.out.println("是否返回主菜单?Y/N"); if (input.next().equalsIgnoreCase("Y")) mainMenu(); else System.out.println("谢谢使用"); } public static void login() { Scanner input = new Scanner(System.in); System.out.println("输入用户名"); String uname = input.next(); System.out.println("输入密码"); String pwd = input.next(); if (uname.equals("admin") && pwd.equals("admin")) System.out.println("成功"); else System.out.println("失败"); returnMain(); } public static void main(String[] args) { mainMenu(); } }