java第八次作业
1、编写一个简单程序,要求数组长度为5,分别赋值10,20,30,40,50,在控制台输出
该数组的值。(知识点:数组定义和创建、一维数组初始化)[必做题]?
package wjy21; public class wjy1 { public static void main(String[] args) { int a[] = { 10, 20, 30, 40, 50 }; for (int i = 0; i < a.length; i++) { System.out.println(a[i]); } } }
2、将一个字符数组的值(neusofteducation)拷贝到另一个字符数组中。(知识点:数组复制) [必做题]?
package wjy21; public class wjy2 { public static void main(String[] args) { char[]a=new char []{'n','e','u','s','o','f','t','e','d','u','c','a','t','i','o','n'}; char b[]=new char[16]; for (int i = 0; i <a.length; i++){ b[i]=a[i]; } System.out.println(b); } }
3、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。(知识点:Arrays.sort排序、冒泡排序)
package wjy21; public class wjy2 { public static void main(String[] args) { int a[] = { 1, 6, 2, 3, 9, 4, 5, 7, 8 }; for (int i = 0; i < a.length - 1; i++) { for (int j = 0; j < a.length - i - 1; 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); } } }
4.输出一个double型二维数组(长度分别为5、4,值自己设定)的值。(知识点:数组定义和创建、多维数组初始化、数组遍历
package wjy21; public class wjy2 { public static void main(String[] args) { double a[][]={{1,2,3,4,},{2,3,4,5},{6,7,8,9},{2,1,3,4},{1,4,5,6}}; for (int i = 0; i < a.length; i++) { for (int j = 0; j < a[0].length; j++) { System.out.print(a[i][j]+" "); } System.out.println(); } } }
5、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。(知识点:数组遍历、数组元素访问) [必做题]?
package aa; public class Test5 { /** * @param args */ public static void main(String[] args) { // TODO Auto-generated method stub double a[] ={18,25,7,36,13,2,89}; double max = a[0]; int maxxb = 0; double min = a[0]; int minxb = 0; for (int i = 0; i < a.length; i++) { if (a[i] > max) { max = a[i]; maxxb = i; } if (a[i] < min) { min = a[i]; minxb = i; } } System.out.println("最大的数为"+max+"下标为"+maxxb); System.out.println("最小胡数为"+min+"下标为"+minxb); } }
6、将一个数组中的元素逆序存放(知识点:数组遍历、数组元素访问)
package wjy21; public class wjy2 { public static void main(String[] args) { int a[] = new int[5]; for (int i = 0; i < a.length; i++) { a[i] = i; } for (int i : a) { System.out.print(i + " "); } System.out.println(); for (int i = 0; i < a.length; i++) { for (int j = i; j < a.length; j++) { int temp = a[i]; a[i] = a[j]; a[j] = temp; } } for (int i : a) { System.out.print(i + " "); } } }
7. 将一个数组中的重复元素保留一个其他的清零。(知识点:数组遍历、数组元素访问)
package wjy21; public class wjy2 { public static void main(String[] args) { int[] a ={1,1,1,3,4,4,9,9,6,6,6,7,8,8,8,4,1}; for (int i : a) { System.out.print(i+"\t "); } System.out.println(); 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.print(i+"\t "); } } }
8.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。(知识点:数组遍历、数组元素访问)
package wjy21; public class wjy2 { public static void main(String[] args) { int a[] =new int[]{-10,2,3,246,-100,0,5}; int sum = 0; int max =a[0]; int min =a[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]; } System.out.println("最大值" +max); System.out.println("最小值" +min); System.out.println("平均值:" +sum*1.0/a.length); } }
9.使用数组存放裴波那契数列的前20项 ,并输出 1 1 2 3 5 8 13 21
public class wjy2 { 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 : a) { System.out.print(i +" "); } } }
10.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 diqizhou; import java.util.Arrays; import java.util.Random; import java.util.Scanner; public class Test { public static void main(String[] args) { // TODO Auto-generated method stub Scanner input = new Scanner(System.in); Random r = new Random();// 生成随机数 int a[] = new int[10]; for (int i = 0; i < a.length; i++) { a[i] = r.nextInt(100); } Arrays.sort(a);// Arrays.sort排序及foreach遍历 for (int i : a) { System.out.print(i + "\t"); } System.out.println();// 冒泡排序 for (int i = 0; i < a.length; i++) { for (int j = i; j < a.length; j++) { if (a[i] < a[j]) { int temp = a[i]; a[i] = a[j]; a[j] = temp; } } } for (int i : a) { System.out.print(i + "\t"); } } }