java第八次上机+练习
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]?
public class work8 { /** * @param args */ public static void main(String[] args) { // TODO Auto-generated method stub int a[]={10,20,30,40,50}; for (int i = 0; i < a.length; i++) { System.out.print(" "+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]?
public class work8 { /** * @param args */ public static void main(String[] args) { // TODO Auto-generated method stub char a[]={'n','e','u','s','o','f','t','e','d','u','c','a','t','i','o','n'}; char b[]=new char[a.length]; System.arraycopy(a, 0, b, 0,a.length); for (int i = 0; i < b.length; i++) { System.out.print(a[i]); } } }
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)
import java.util.Arrays; public class work8 { /** * @param args */ public static void main(String[] args) { // TODO Auto-generated method stub int a[]={1,6,2,3,9,4,5,7,8}; Arrays.sort(a); for(int i:a){ System.out.print(" "+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)
public class work8 { /** * @param args */ public static void main(String[] args) { // TODO Auto-generated method stub double a[][]=new double[5][4]; for (int i = 0; i < 5; i++) { for (int j = 0; j < 4; j++) { a[i][j]=j; } } for (int i = 0; i < 5; i++) { for (int j = 0; j <4; 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]?
作业
public class work8 { /** * @param args */ 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 maxidx=0; for (int i = 0; i < a.length; i++) { if(a[i]>max){ max=a[i]; maxidx=i; } } System.out.println("最大值是:"+max); System.out.println("下标是:"+maxidx); } }
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)
import java.util.Scanner; public class work8 { /** * @param args */ public static void main(String[] args) { // TODO Auto-generated method stub Scanner input=new Scanner(System.in); int a[]=new int[5]; for (int i = a.length; i >0; i--) { a[i-1]=input.nextInt(); } System.out.println("逆序输出:"); for (int i = 0; i < a.length; i++) { System.out.print(a[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)
public class work8 { /** * @param args */ public static void main(String[] args) { // TODO Auto-generated method stub int [] a={5,5,5,4,2,9}; 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.println(i); } } }
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)
public class work8 { /** * @param args */ public static void main(String[] args) { // TODO Auto-generated method stub int a[]={-10,2,3,246,-100,0,5}; int max=a[0],min=a[0],sum=0; double pingjun=0; for (int i = 0; i < a.length; i++) { sum+=a[i]; pingjun=sum/7; if(a[i]>max){ max=a[i]; } if(a[i]<min){ min=a[i]; } } System.out.println("平均值:"+pingjun); System.out.println("最大值:"+max); System.out.println("最小值:"+min); } }
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 work8 { /** * @param args */ public static void main(String[] args) { // TODO Auto-generated method stub int a[] = new int[20]; a[0] = 1; a[1] = 1; System.out.println("斐波那契数列前20项:"); System.out.print(a[0]+" "+a[1]+" "); for(int i = 2; i < 20; i++){ a[i] = a[i - 1] + a[i - 2]; System.out.print(a[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
import java.util.Arrays; import java.util.Random; public class work8 { /** * @param args */ public static void main(String[] args) { // TODO Auto-generated method stub Random a=new Random(); int b[]=new int[10]; for (int i = 0; i < b.length; i++) { b[i]=a.nextInt(100); System.out.println(b[i]); } System.out.println("排序:"); Arrays.sort(b); for(int i:b){ System.out.print(i+" "); } } }