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 test; import java.util.Arrays; import java.util.Random; import java.util.Scanner; public class acc { public static void main(String[] args) { // TODO Auto-generated method stub int a[] = {1,6,5,7,8,9,4,3,2, }; Arrays.sort(a); for(int i:a) { System.out.print(" "+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 test; import java.util.Arrays; import java.util.Random; import java.util.Scanner; public class acc { 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+j;}} 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 test; import java.util.Arrays; import java.util.Random; import java.util.Scanner; public class acc { 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],maxid = 0; for(int i=1;i<a.length;i++) { if(max<a[i] ){ max=a[i]; maxid=i;}} System.out.print("最大数是:"+max+"其下标为:"+maxid);}}
4. 将一个数组中的元素逆序存放
package test; import java.util.Arrays; import java.util.Random; import java.util.Scanner; public class acc { public static void main(String[] args) { // TODO Auto-generated method stub int[] a= {1,3,2,4,6,7,8}; int b; for(int i=0;i<a.length/2;i++) { b=a[i]; a[i]=a[a.length-i-1]; a[a.length-i-1]=b;} for(int i:a) { System.out.print(i+" ");} System.out.println();}}
5.将一个数组中的重复元素保留一个其他的清零
package test; import java.util.Arrays; import java.util.Random; import java.util.Scanner; public class acc { public static void main(String[] args) { // TODO Auto-generated method stub int[] a = { 1, 1, 2, 2, 3, 3, 4, 4,5,5,6,6,7,8 }; boolean[] b = new boolean[a.length]; for (int i = 0; i < a.length - 1; i++) { if (b[i]) { continue; } for (int j = i + 1; j < a.length; j++) { if (a[i] == a[j] && !b[j]) { b[j] = true; } } } for (int i = 0; i < a.length; i++) { if (b[i]) continue; System.out.print(a[i] + " "); } System.out.println(); } }
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 test; import java.util.Arrays; import java.util.Random; import java.util.Scanner; public class acc { public static void main(String[] args) { // TODO Auto-generated method stub int a[] = { -10, 2, 3, 246, -100, 0, 5 }; int max = a[0]; int min = a[0]; double sum = 0; for (int i = 1; i < a.length; i++) { if (a[i] > max) { max = a[i]; } if (a[i] < min) { min = a[i]; } } for (int i = 0; i < a.length; i++) { sum += a[i]; } System.out.println("最大值为:" + max); System.out.println("最小值为:" + min); System.out.println("平均值为:" + sum / a.length); } }
7.使用数组存放裴波那契数列的前20项 ,并输出
package test; import java.util.Arrays; import java.util.Random; import java.util.Scanner; public class acc { 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) { } 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 test; import java.util.Arrays; import java.util.Random; import java.util.Scanner; public class acc { public static void main(String[] args) { // TODO Auto-generated method stub Random r = new Random(); int[] a = new int[10]; System.out.println("输出数组为"); for (int i = 0; i < a.length; i++) { int b = r.nextInt(101); a[i] = b; System.out.print(" " + a[i]); } Arrays.sort(a); System.out.println("\n排序后的数组为"); 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
package test; import java.util.Random; import java.util.Scanner; public class abc { public static void Menu_main() { Scanner input=new Scanner(System.in); System.out.println("\t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"); int num=input.nextInt(); switch(num) { case 1: Menu_1(); break; case 2: Menu_2(); break; case 3: Menu_3(); break; case 4: break; default : System.out.println("输入错误"); break; } } public static void Menu_1() { Scanner input=new Scanner(System.in); System.out.println("\t登录"); System.out.println("返回主菜单:1"); System.out.println("退出:2"); int num=input.nextInt(); switch(num) { case 1: Menu_main(); case 2: return; } } public static void Menu_2() { Scanner input=new Scanner(System.in); System.out.println("\t注册"); System.out.println("返回主菜单:1"); System.out.println("退出:2"); int num=input.nextInt(); switch(num) { case 1: Menu_main(); case 2: return; } } public static void Menu_3() { Scanner input=new Scanner(System.in); System.out.println("\t幸运抽奖"); System.out.println("返回主菜单:1"); System.out.println("退出:2"); int num=input.nextInt(); switch(num) { case 1: Menu_main(); case 2: return; } } public static void main(String[] args) { Menu_main(); } }