第八周作业
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 text; public class test1 { /** * @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.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 text; import java.util.Arrays; public class test2 { /** * @param args */ public static void main(String[] args) { // TODO Auto-generated method stub char []x={'c','h','i','n','a'}; char []y=new char[10]; System.arraycopy(x,0,y,0,5); System.out.println(Arrays.toString(y)); } }
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 text; public class test3 { /** * @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 - 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); } } }
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 text; public class test4 { /** * @param args */ public static void main(String[] args) { // TODO Auto-generated method stub int [][]a=new int[5][4]; for (int i = 0; i < a.length; i++) { for (int j = 0; j < a[i].length; j++) { a[i][j]=i+j; } } System.out.println("矩阵是"); 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) [必做题]? package text; public class test5 { /** * @param args */ public static void main(String[] args) { // TODO Auto-generated method stub int a[]={18,25,7,6,13,2,89,63}; int max=a[0],maxXB=0; for(int i=1;i<a.length;i++){ if(a[i]>max) max=a[i]; maxXB=i; } System.out.println("最大值为"+max+",下标为"+maxXB); } }
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 text; public class text6 { public static void main(String[] args) { // TODO Auto-generated method stub int s[] ={1,3,5,7,9,11,13,15,17,19}; int t; for (int i = 0,j=s.length-1;i<j; i++,j--) { t=s[i]; s[i]=s[j]; s[j]=t; } for (int i = 0; i < s.length; i++) { System.out.print(s[i]+" "); } System.out.println(); }
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 text; public class text7{ public static void main(String[] args) { // TODO Auto-generated method stub int a[]={2,4,6,8,2,5,4,2}; for (int i = 0; i < a.length; i++) { for (int j = 0; j < a.length; j++) { if(a[i]==a[j]){ if(i!=j){ a[j]=0; } } } System.out.println(a[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) package text; public class text8 { public static void main(String[] args) { // TODO Auto-generated method stub int a[]={-10,2,3,246,-100,0,5}; int sum=0; int max=0; int min=0; double j=0; for (int i = 0; i < a.length; i++) { sum+=a[i]; if(max<a[i]){ max=a[i]; } if(min>a[i]){ min=a[i]; } j=i+1; } System.out.println("平均值是:"+sum/j); System.out.println("最大值是:"+max); System.out.println("最小值是:"+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 package test; import java.util.Arrays; import java.util.Scanner; public class text9 { public static void main(String[] args) { // TODO 自动生成的方法存根 int num[] = new int[20]; num[0] = 1; num[1] = 1; System.out.println("斐波那契数列前20项的值如下:"); System.out.print(num[0]+" "+num[1]+" "); for(int i = 2; i < 20; i++){ num[i] = num[i - 1] + num[i - 2]; System.out.print(num[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 test; import java.util.Arrays; import java.util.Scanner; public class text10 { public static void main(String[] args) { Scanner input= new Scanner(System.in); int temp=0; int[] a = new int[10]; for (int i = 0; i < 10; i++) { a[i] = input.nextInt(); } for (int i = 0; i < 10; i++) { for (int j = i + 1; j < 10; j++) { if (a[i] > a[j]) { temp = a[i]; a[i] = a[j]; a[j] = temp; } } } for (int i = 0; i < 10; i++) { System.out.print(a[i] + " "); } } }