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 com.zy.ktlx; public class test5 { /** * @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 com.zy.ktlx; import java.util.Arrays; public class test4 { /** * @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[18]; System.arraycopy(a, 0,b , 0, 16); 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 com.zy.ktlx; 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 com.zy.ktlx; public class test2 { /** * @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]=j; } } System.out.println("二维数组为"); 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)
package com.zy.ktlx; public class test1 { /** * @param args */ public static void main(String[] args) { // TODO Auto-generated method stub int a[]={18,25,7,36,13,2,89,63}; int idx=0; int max=0; for (int i = 0; i < a.length; i++) { if (a[i]>max) { max=a[i]; idx=i; } } System.out.println("最大值是"+max+"下标是"+idx); } }
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 com.dq.homework; public class test1 { /** * @param args */ public static void main(String[] args) { // TODO Auto-generated method stub int a[]={1,2,3,4,5}; for (int i = 0; i < a.length; i++) { System.out.println(a[i]); } for (int j = 4; j >0; j--) { System.out.println(a[j]); } System.out.println(a[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) [选作题]课后作业•
package com.dq.homework; 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); int a[]=new int[5]; System.out.println("输入数组元素"); for (int i = 0; i < a.length; i++) { a[i]=input.nextInt(); } for (int i= 0; i< a.length; i++) { for (int j = i+1; j < a.length; j++) { if(a[i]==a[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 com.dq.homework; import java.util.Arrays; 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 }; double average = 0; double sum = 0; for (int i = 0; i <7; i++) { sum += a[i]; } average = sum / 7; int max = a[0]; int min = a[0]; for (int i = 1; i < 7; i++) { if (a[i] > max) { max = a[i]; } if (a[i] < min) { min = a[i]; } } System.out.println("最大值是"+max); System.out.println("最小值是"+min); System.out.println("平均值是"+average); } }
9、使用数组存放裴波那契数列的前20项 ,并输出
package com.dq.homework; public class homework2 { /** * @param args */ public static void main(String[] args) { // TODO Auto-generated method stub int a[]=new int[20]; a[0]=a[1]=1; for (int i = 2; i < a.length; i++) { a[i]=a[i-1]+a[i-2]; } 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 com.dq.homework; import java.util.Arrays; import java.util.Random; public class test5 { /** * @param args */ public static void main(String[] args) { // TODO Auto-generated method stub int a[]=new int[10]; Random r=new Random(); for (int i = 0; i < a.length; i++) { a[i]=r.nextInt(101); } for (int i = 0; i < a.length; i++) { System.out.println(a[i]); } System.out.println("排序后为"); Arrays.sort(a); for (int i = 0; i < a.length; i++) { System.out.println(a[i]); } } }