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]?
package task427; public class shangji { /** * @param args */ public static void main(String[] args) { // TODO Auto-generated method stub //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。 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 sj; public class sj2 { /** * @param args */ public static void main(String[] args) { // TODO Auto-generated method stub int a[]={1,6,2,3,9,4,5,7,8}; int b[]=new int[9]; System.arraycopy(a,0,b,0,9); 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)
package task427; import java.util.Arrays; public class shangji { /** * @param args */ public static void main(String[] args) { // TODO Auto-generated method stub int a[] =new int[]{1,6,2,3,9,4,5,7,8}; Arrays.sort(a); for (int i : a) { System.out.print(i); } System.out.println(); 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; } } } for (int i = 0; i < a.length; i++) { System.out.print(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)
package sj; public class sj4 { /** * @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+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 sj; public class sj5 { /** * @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=0,maxidx=0; for (int i = 0; i < a.length; i++) { for (int j = 0; j < a.length; j++) { if (max<a[i]) { max=a[i]; maxidx=i; } } } System.out.println("最大值"+max+"下标是"+maxidx); } }
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)
package task427; public class task1 { /** * @param args */ public static void main(String[] args) { // TODO Auto-generated method stub //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) int a[] =new int[]{1,2,3,4,5,6,7,8,9,10}; for (int i : a) { System.out.print(i+" "); } System.out.println(); for (int i = 0; i < a.length; i++) { for (int j = i; j < a.length; j++) { int temp =a[i]; a[i] =a[j]; a[j] =temp; } } for (int i : a) { System.out.print(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)
package task427; public class task2 { /** * @param args */ public static void main(String[] args) { // TODO Auto-generated method stub int[] a ={1,1,1,3,3,4,5,6,6,8,8,9,9,10}; for (int i : a) { System.out.print(i +" "); } System.out.println(); 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; } } for (int i : a) { System.out.print(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 task427; public class task3 { /** * @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,max =a[0],min =a[0]; for (int i = 0; i < a.length; i++) { if (min > a[i]) { min = a[i]; } if (max < a[i]) { max = a[i]; } sum +=a[i]; } System.out.println("最小值是" +min); System.out.println("最大值是" +max); System.out.println("平均值是:" +sum*1.0/a.length); } }
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 task427; public class task4 { /** * @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 : a) { System.out.print(i + " "); } } }