Java第六次作业
1、给定一个有9个整数(1,6,2,3,9,4,5,7,8)的数组,先排序,然后输出排序后的数组的值
package aaa; import java.util.Arrays; import java.util.Iterator; public class Text1 { public static void main(String[] args) { // TODO Auto-generated method stub int[]a=new int[9]; a= new int[]{1,6,2,3,9,4,5,7,8}; Arrays.sort(a); for(int d:a) { System.out.println(d); } } }
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 aaa; import java.util.Iterator; public class Text1 { public static void main(String[] args) { // TODO Auto-generated method stub double a[][]= {{1,2,3,4}, {5,6,7,8}, {1,2,3,4}, {5,6,7,8}, {1,2,3,4}}; 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 aaa; import java.util.Iterator; public class Text1 { public static void main(String[] args) { // TODO Auto-generated method stub int a[]= {18,25,7,36,13,2,89,63}; int x=0; int y=0; for (int i = 0; i < a.length; i++) { if(x<=a[i]) { x=a[i]; y=i; } } System.out.println("最大数为"+x+"下标为"+y); } }
4、将一个数组中的元素逆序存放
package aaa; import java.util.Iterator; public class Text1 { public static void main(String[] args) { // TODO Auto-generated method stub int a[]= {18,25,7,36,13,2,89,63}; for (int i = a.length-1; i >=0; i--) { System.out.println(a[i]); } } }
5、将一个数组中的重复元素保留一个其他的清零
package aaa; import java.util.Iterator; public class Text1 { public static void main(String[] args) { // TODO Auto-generated method stub int a[]= {1,1,2,2,3,3}; for (int i = 0; i < a.length; i++) { for (int j = i+1; j < a.length; j++) { if(a[i]==a[j]) { a[j]=0; } } } for(int i:a) { System.out.println(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。
package aaa; import java.util.Iterator; public class Text1 { public static void main(String[] args) { // TODO Auto-generated method stub int a[]= {-10,2,3,246,-100,0,5}; int sum=0; int x=a[0]; int y=a[0]; for (int i = 0; i < a.length; i++) { sum+=a[i]; if(x<=a[i]) x=a[i]; if(y>=a[i]) y=a[i]; } double z=sum/a.length; System.out.println("平均值为"+z+",最大值为"+x+",最小值为"+y); } }
7、使用数组存放裴波那契数列的前20项 ,并输出
package aaa; import java.util.Iterator; public class Text1 { public static void main(String[] args) { // TODO Auto-generated method stub 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:a) { System.out.println(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
package aaa; import java.util.Arrays; import java.util.Iterator; import java.util.Random; public class Text1 { public static void main(String[] args) { // TODO Auto-generated method stub 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:a) { System.out.println(i); } System.out.println(); Arrays.sort(a); for(int i:a) { System.out.println(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
package aaa; import java.util.Arrays; import java.util.Iterator; import java.util.Random; import java.util.Scanner; public class Text1 { public static void mainmenu() { System.out.println("主菜单"); 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 a=input.nextInt(); switch(a) { case 1: denglu(); break; case 2: zhuce(); break; case 3: choujiang(); break; case 4: System.out.println("为您退出"); break; } } public static void denglu() { System.out.println("请输入账号"); System.out.println("请输入密码"); Scanner input =new Scanner(System.in); String a=input.next(); String b=input.next(); if(a.equals(b)) { System.out.println("登录成功,返回主菜单"); mainmenu(); }else { System.out.println("登陆失败,请重试"); denglu(); } } public static void zhuce() { System.out.println("请输入账号"); Scanner input =new Scanner(System.in); String a=input.next(); System.out.println("请输入密码"); String b=input.next(); if(a.equals(b)) { System.out.println("注册成功,返回主菜单"); mainmenu(); }else { System.out.println("注册失败,请重试"); zhuce(); } } public static void choujiang() { Random r=new Random(); Scanner input =new Scanner(System.in); System.out.println("请输入您选择的号码(1-99)"); int a=input.nextInt(); if(a==r.nextInt(100)) { System.out.println("恭喜您,抽中了,为您返回主菜单"); mainmenu(); }else { System.out.println("没抽中,返回主菜单"); mainmenu(); } } public static void main(String[] args) { // TODO Auto-generated method stub mainmenu(); } }