java第六次作业
public static void main(String[] args) { // TODO Auto-generated method stub int a[] = {2,4,6,4,8,9,2 }; System.out.println("Arrays.sort排序:"); Arrays.sort(a); for (int i : a) { System.out.println(i); } System.out.println("冒泡排序:"); for (int i = 0; i < a.length - 1; i++) { for (int j = 0; j < a.length - 1 - i; j++) { if (a[j] > a[j + 1]) { int temp = a[j]; a[j] = a[j + 1]; a[j + 1] = temp; } } } for (int i : a) { System.out.println(i); } } }
2.输出一个double型二维数组(长度分别为5、4,值自己设定)的值
package six; public class Test { public static void main(String[] args) { // TODO Auto-generated method stub double a[][] = new double[5][4]; for (int i = 0; i < a.length; i++) { for (int j = 0; j < a[i].length; j++) { a[i][j] = i; } } for (int i = 0; i < a.length; i++) { for (int j = 0; j < a[i].length; j++) { System.out.print(a[i][j]+" "); } System.out.println(); } } }
3.在一个有8个整数(18,25,7,36,13,2,89,63)的数组中找出其中最大的数及其下标
package six; public class Test { public static void main(String[] args) { // TODO Auto-generated method stub int a[]={18,25,7,36,13,2,89,63}; int max=a[0]; int index=0; for (int i = 0; i < a.length; i++) { if (a[i]>max) { max=a[i]; index=i; } } System.out.println("数组中的最大值为"+max); System.out.println("下标为"+index); }
4.将一个数组中的元素逆序存放
public class six { public static void main(String[] args) { // TODO Auto-generated method stub int a[]={18,25,7,36,13,2,89,63}; System.out.println("倒序后为:"); for (int i = 7; i >= 0; i--) { System.out.print (" "+a[i]); } } }
5.将一个数组中的重复元素保留一个其他的清零。
public class six { public static void main(String[] args) { int a[]={18,25,7,36,13,2,89,63,25,18}; for (int i = 0; i < a.length; i++) { for (int j = 0; j < a.length; j++) { if (a[i]==a[j] && i!=j) { a[j]=0; } } } for (int i : a) { System.out.print(" "+i); } } }
6.给定一维数组{ -10,2,3,246,-100,0,5},计算出数组中的平均值、最大值、最小值
public class six { public static void main(String[] args) { int a[]={-10,2,3,246,-100,0,5}; int max=a[0]; int min=a[0]; double sum=0; for (int i = 0; i < a.length; i++) { if (max<a[i]) { max=a[i]; } if (min>a[i]) { min=a[i]; } sum+=a[i]; } sum=sum/7; System.out.println("最大值"+max); System.out.println("最小值"+min); System.out.println("平均值"+sum); } }
7.使用数组存放裴波那契数列的前20项 ,并输出
public class six { public static void main(String[] args) { int[] a = new int[20]; a[0] = 1; a[1] = 1; for (int i = 2; i < a.length; i++) { a[i] = a[i - 1] + a[i - 2]; } for (int i = 0; i < 8; i++) { System.out.print(a[i] + " "); } } }
8.生成一个长度为10的随机整数数组(每个数都是0-100之间),输出,排序后,再输出
public class six { public static void main(String[] args) { Random r = new Random(); int a[] = new int[10]; for (int i = 0; i < a.length; i++) { a[i] = r.nextInt(101); } for (int i = 0; i < a.length; i++) { System.out.print(a[i] + " "); } Arrays.sort(a); System.out.println(); for (int i = 0; i < a.length; i++) { System.out.print(a[i]+" "); } } }
9.做一个菜单切换程序。主菜单1.登陆 2.注册 3幸运抽奖 4 退出。每个菜单可以返回主菜单
public class six1 { public static void showMain() { 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"); Scanner input = new Scanner(System.in); int i = input.nextInt(); switch (i) { case 1: login(); break; case 2: zhuce(); break; case 3: choujiang(); break; case 4: tuichu(); break; } } public static void login() { System.out.println("輸入用戶名"); Scanner input = new Scanner(System.in); String name = input.next(); System.out.println("输入密码"); String pwd = input.next(); if (name.equals(pwd)) { System.out.println("登录成功"); } else { System.out.println("登录失败"); } System.out.println("是否返回主菜单?Y/N"); if (input.next().equalsIgnoreCase("y")) { showMain(); } else { System.out.println("谢谢使用"); } } public static void zhuce() { System.out.println("请输入用户名"); Scanner input = new Scanner(System.in); String name = input.next(); System.out.println("输入密码"); String pwd = input.next(); System.out.println("注册成功"); System.out.println("是否返回主菜单?Y/N"); if (input.next().equalsIgnoreCase("y")) { showMain(); } else { System.out.println("谢谢使用"); } } public static void choujiang() { Random r = new Random(); System.out.println("幸运抽奖,请输入一个数(0-100)"); Scanner input = new Scanner(System.in); int i = input.nextInt(); int q = r.nextInt(101); if (i == q) { System.out.println("恭喜你,中奖了,再抽一次"); choujiang(); } else { System.out.println("很遗憾,未中奖,返回主菜单"); showMain(); } } public static void tuichu() { System.out.println("谢谢使用"); } public static void main(String[] args) { showMain(); } }