java第8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 jj; import java.util.Scanner; public class a { /** * @param args */ public static void main(String[] args) { // TODO Auto-generated method stub int [] a=new int[5]; Scanner input=new Scanner(System.in); for (int i = 0; i < a.length; i++) { a[i]=input.nextInt(); } 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 jj; public class b { /** * @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(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)
package jj; public class c { /** * @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 = 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 jj; import java.util.Scanner; public class d { /** * @param args */ public static void main(String[] args) { // TODO Auto-generated method stub double [][]a=new double[5][4]; Scanner input=new Scanner(System.in); System.out.println("矩阵是"); for (int i = 0; i < a.length; i++) { for (int j = 0; j < a[i].length; j++) { a[i][j]=input.nextInt(); } } 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 jj; public class e { /** * @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],id=0; for (int i = 1; i < a.length; i++) { if (a[i]>max) { max=a[i]; id=i; } } System.out.println("最大"+max+"下标"+id); } }
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]
package cc; import java.util.Scanner; public class test1 { /** * @param args */ public static void main(String[] args) { // TODO Auto-generated method stub Scanner input=new Scanner(System.in); System.out.println("请输入"); int a[]=new int[5]; for (int i = a.length; i >0; i--) { a[i-1]=input.nextInt(); } System.out.println("倒序输出"); for (int i = 0; i < a.length; 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。
package cc; import java.util.Scanner; public class test2 { /** * @param args */ public static void main(String[] args) { // TODO Auto-generated method stub Scanner input=new Scanner(System.in); int a[]=new int[5]; System.out.println("请输入"); for (int i = 0; i < a.length; i++) { a[i]=input.nextInt(); } for (int i = 0; i < a.length-1; i++) { for (int j = i+1; j < a.length; j++) { if(a[i]==a[j]){ a[j]=0; } } } for (int i = 0; i < a.length; i++) { 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。
package cc; import java.util.Scanner; public class test3 { /** * @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]; int sum=0; double avg=0; for (int i = 0; i < a.length; i++) { sum+=a[i]; avg=sum/7; if(a[i]>max){ max=a[i]; } if(a[i]<min){ min=a[i]; } }System.out.println("平均值="+avg); 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
package cc; import java.util.Scanner; public class test4 { /** * @param args */ public static void main(String[] args) { // TODO Auto-generated method stub int a[]=new int[20];a[0]=1; int x=1; int y=1; int z=1; for (int i = 1; i < a.length; i++) { a[i]=z; z=x+y; x=y; y=z; } for (int i = 0; i < a.length; 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
package cc; import java.util.Random; public class test5 { /** * @param args */ public static void main(String[] args) { // TODO Auto-generated method stub Random random = new Random(10); int a[] = new int[10]; for (int i = 0; i < a.length; i++) { a[i] = random.nextInt(100); System.out.println(a[i]); } System.out.println(); 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; } } } System.out.print("排序后结果为"); System.out.println(); for (int i = 0; i < a.length; i++) { System.out.println( a[i]); } } }