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 aaaaa;
import java.util.Arrays;
public class aaaaa {
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 aaaaa;
public class aaaaa {
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 aaaaa;
public class aaaaa {
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 aaaaa;
public class aaaaa {
public static void main(String[] args) {
// TODO Auto-generated method stub
int[] a= {1,2,3,4,5,6,7};
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 aaaaa;
public class aaaaa {
public static void main(String[] args) {
// TODO Auto-generated method stub
int[] a= {1,1,2,2,3,3,4,5};
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。
import java.util.aaaaa;
public class aaaaa {
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 aaaaa;
public class aaaaa {
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 aaaaa;
import java.util.Arrays; import java.util.Random; import java.util.Scanner;
public class aaaaa{
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
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package aaaaa;
import java.util.Random; import java.util.Scanner;
public class aaaaa { 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(); }
} |