Java第八周上机练习+作业
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)
packageaaa; publicclass Test1 { /** * @paramargs */ publicstaticvoid 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.println(a[i]); } } }
2.将一个字符数组的值(neusoft)拷贝到另一个字符数组中。(知识点:数组复制)
/** * @paramargs */ publicstaticvoid main(String[] args) { // TODO Auto-generated method stub char []x={'n','e','u','s','o','f','t'}; char []y=newchar[x.length]; System.arraycopy(x, 0, y, 0,x. length); for(char i:y){ System.out.println(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)
packageaaa; publicclass Test2 { /** * @paramargs */ publicstaticvoid 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 - 1; i++) { for (int j = 0; j <a.length - 1 - i; 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); } } }
packageaaa; importjava.util.Arrays; publicclass Test2 { /** * @paramargs */ publicstaticvoid 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 - 1; i++) { for (int j = 0; j <a.length - 1 - i; j++) { } } Arrays.sort(a); 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)
packageaaa; importjava.util.Arrays; publicclass Test2 { /** * @paramargs */ publicstaticvoid main(String[] args) { // TODO Auto-generated method stub double a[][] = newdouble[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.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)
packageaaa; publicclass Test3 { /** * @paramargs */ publicstaticvoid main(String[] args) { // TODO Auto-generated method stub int []a={18,25,7,36,13,2,89,63}; int max=a[0]; int i; inty; for ( i = 0; i <a.length; i++) { if(a[i]>max) max=a[i]; } y=i-1; System.out.println("最大值是"+max); System.out.println("下标是"+y); } }
作业
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 Text1 { /** * @param args */ public static void main(String[] args) { // TODO Auto-generated method stub Scanner input = new Scanner(System.in); System.out.println("输入数组中的元素个数"); int a = input.nextInt(); int b[] = new int[a]; System.out.println("输入数组元素:"); for (int i = 0; i < a; i++) { b[i] = input.nextInt(); } for (int j = a - 1; j > 0; j--) { System.out.print(b[j]); } System.out.println(b[0]); } }
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 Text2 { /** * @param args */ public static void main(String[] args) { // TODO Auto-generated method stub int a[] = new int[] { 6,8,8,5,5,4,6}; 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); } } }
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 Text2 { /** * @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]; } int pj=sum/7; System.out.println("最大值是" + max); System.out.println("最小值是" + min); System.out.println("平均值是" + pj); } }
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 Text2 { /** * @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 < a.length; i++) { a[i] = a[i - 1] + a[i - 2]; } for (int i = 0; i < 8; i++) { System.out.println(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; import java.util.Scanner; public class Text2 { /** * @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(101); } for (int i = 0; i < a.length; i++) { System.out.println(a[i]); } System.out.println("经排序后 "); Arrays.sort(a); for (int i = 0; i < a.length; i++) { System.out.println(a[i]); } } }