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]
import java.util.Random; import java.util.Scanner; public class ss { /** * @param args */ public static void main(String[] args) { // TODO Auto-generated method stub Scanner input=new Scanner(System.in); int []a={10,20,30,40,50}; for (int i = 0; i < a.length; i++) { System.out.print(a[i]); System.out.print(" "); } } }
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]
import java.util.Random; import java.util.Scanner; public class ss { /** * @param args */ public static void main(String[] args) { // TODO Auto-generated method stub Scanner input=new Scanner(System.in); char []a={'b','a'}; char []b=new char[a.length]; System.arraycopy(a, 0, b, 0, a.length); for (int i = 0; i < b.length; i++) { System.out.println(b[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
Arrays.sort排序
import java.util.Random; import java.util.Scanner; public class ss { /** * @param args */ public static void main(String[] args) { // TODO Auto-generated method stub int []a={1,6,2,3,9,4,5,7,8}; java.util.Arrays.sort(a); for (int i = 0; i < a.length; i++) { System.out.println(a[i]); } } }
冒泡排序
import java.util.Random; import java.util.Scanner; public class ss { /** * @param args */ public static void main(String[] args) { // TODO Auto-generated method stub int []a={1,6,2,3,9,4,5,7,8}; for (int i = 0; i < a.length; i++) { for (int j = i+1; j < a.length-1; j++) { if(a[j]>a[j+1]){ int c=a[j]; a[j]=a[j+1]; a[j+1]=c; } } } for (int i = 0; i < a.length; i++) { System.out.println(a[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)
import java.util.Random; import java.util.Scanner; public class ss { /** * @param args */ 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; } } 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.print(" "); } 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
import java.util.Random; import java.util.Scanner; public class ss { /** * @param args */ public static void main(String[] args) { // TODO Auto-generated method stub int []a = new int[]{ 18, 25, 7, 36, 1, 2, 89, 63 }; int s = a[0]; int c = 0; for (int i = 0; i < a.length; i++) { if (a[i] > s) { s = a[i]; c = i; } } System.out.println("下标为" + c); System.out.println("最大值为" + s); } }
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) [选作题]•
import java.util.Random; import java.util.Scanner; public class ss { /** * @param args */ public static void main(String[] args) { // TODO Auto-generated method stub int a[]=new int[3]; a[0]=1; a[1]=5; a[2]=3; int b[]=new int[a.length]; System.arraycopy(a, 0, b, 0,a.length); for(int i=0;i<=2;i++){ a[i]=b[2-i]; System.out.println(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) [选作题]课后作业•
import java.util.Random; import java.util.Scanner; public class ss { /** * @param args */ public static void main(String[] args) { // TODO Auto-generated method stub int a[] = new int[] { 1,0,0,2,3,4,4}; 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 x: a) { System.out.print(x); System.out.print(" "); } } }
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)
import java.util.Random; import java.util.Scanner; public class ss { /** * @param args */ public static void main(String[] args) { // TODO Auto-generated method stub 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++) { sum += a[i]; if (a[i] > max) max = a[i]; if (a[i] < min) min = a[i]; } double c=sum/7.0; System.out.println("最大值是" + max); System.out.println("最小值是" + min); System.out.println("平均值是" + c); } }
9、使用数组存放裴波那契数列的前20项 ,并输出
import java.util.Random; import java.util.Scanner; public class ss { /** * @param args */ 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 < 20; i++) { a[i] = a[i - 1] + a[i - 2]; } for (int i = 0; i < 8; i++) { System.out.print(a[i]); System.out.print(" "); } } }
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.Random; import java.util.Scanner; import java.util.Arrays; public class ss { /** * @param args */ public static void main(String[] args) { // TODO Auto-generated method stub int a[]=new int[10]; Random x=new Random(); System.out.println("创建的100以内的随机数"); for (int i = 0; i < a.length; i++) { a[i]=x.nextInt(100); } for (int i = 0; i < a.length; i++) { System.out.print(a[i]+" "); } System.out.println(); System.out.println("排序后"); Arrays.sort(a); for (int i = 0; i < a.length; i++) { System.out.print(a[i]+" "); } } }