《Java程序设计案例教程（微课版）》 实验八 一维数组.docx

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1、实验八一维数组一、实验目的1、数组的声明，内存分配；2、数组的应用。二、实验内容1、借助一维数组实现求某班Java成绩的平均分，班级人数和成绩从键盘输入。源程序：import j ava.util Scanner;public class求班级平均分(static double qiuhe(double b) double sum = 0;for (int i = 0; i b.length; i+) sum = sum + bi;return sum;static double pingjunzhi(double b) double mean = 0;man = qiuhe(b) / b.l

2、ength; return mean;public static void main(String args) / TODO自动生成的方法存根Scanner in=new Scanner(System.in);int b=0;System. out .printin (”请输入班级人数”);b=in . nextlnt ();double a=new doubleb;double n=0;for (int i=0;ia.length;i+) n=in . nextDoubl();ai=n;Systam. out.printin (班级平均分为“+pingjunzhi (a);2、查找一个数x在

3、数组中出现的次数。 源程序：public class求出现次数(public static void main(String args) / TODO自动生成的方法存根 int x, b, d = 0;Scanner in = new Scanner(System.in);System. out .printIn (请输入要查找的元素”); b = in.nextlnt ();int a = 1, 3, 5, 9, 4, 5r 9, 6, 5, 1 r 3r 4, 7, 9r 5r 6, 4r 1 )；for (int i = 0; i a.length; i+) if (a i = b) d

4、+;) )System, out .printIn (b + ”出现了“ + d + 次3、借助一维数组实现Fibonacci数列前20项的显示。源程序：public class数组求斐波那契且数列public static void main(String args) int a = new int 20;a0 = 1;a1 = 1;for (int i = 2; i a.length; i+) a i = a i - 1 + a i - 2;)for (int i = 0; i =0;i-A j+) double b;b=aa.length-i-1;a a.length-i-1 =a j

5、; / /用中间数交换一下位置就可以了 aj=b;) for (int i=0;ia.length;i+) System.out.print(ai+ n H; ) ) public static void main(String args) Scanner in=new Scanner(System.in); doubl n=0; int c=0;Systm.out. printin (请输入你要倒序的数组的元素的个数”)；/不加这个就 会倒序的时候出现很多零.零(数组初始化0.0) c=in nextlnt ();double b=new double c;for (int i=0;ib.l

6、ength;i+) n=in , nextDouble ();bi=n;)fangfa(b);)5、在数组中查找x是否存在，如果存在将其删除，如果不存在做出提示。 源程序：import java.util.Scanner;public class 数组册U除public static void main(String args) / TODO自动生成的方法存根 Scanner in = new Scanner(System.in);int a = 3, 2, 5, 5r 1, 5, 5, 5, 9 ;System, out .print (之前的数组：H;for (int x : a) Sys

7、tem.out.print(x + ” n);)System.out.printin ();System. out .printIn (“请输入要删除的数字”);int shanchush=in.nextlnt ();int b = a.length;int d = 0, c = 0z e = 0;ffor (int i = 0; i 0) for (int j = 0; j e; j +) for (int i = 0; i a.length; i+) if (a i = shanchush) d = i; C + +； break; )for (int i = d; i a.length

8、- c; i+) a i = a i + 1;)a a.length - 1 = 0;b;/删除一个数后，数组实际长度减一 )System. out .print (之后的数组：”);for (int i = 0; i b; i+) System.out.print(ai + ” H;else System. out .printIn (没有要删除的数字”); )6、在一个升序排列的数组中插入一个值x,使得插入后仍然保持数据的升序。源程序：import java.util.Scanner;public class数组插入元素public static void main(String args

9、) / TODO自动生成的方法存根 int a = 1, 2, 3, 4, 5, 7, 8, 9 ; int b = new inta.length + 1;Seann工 in = new Scanner(System.in);System, out .printIn (”请输入要插入的数”); int c = in.nextlnt ();dij ia: for (int i = 0; i a.length; i + +) if (c = a i) b i = c;for (int j = i; j b.length - 1; j +) bj + 1 = a j ;) break dij ia

10、; else b i = a i; )if (bb.length - 1 c) bb.length - 1 = c;)for (int i = 0; i b.length; i+) System.out.printIn(bi + = n);7、借助任意一种排序算法对某班的Java成绩进行升序排序。源程序：.import java.util.Scanner;public class借用任何一种算法对数组排序public static void main(String args) / TODO自动生成的方法存根Scanner in = new Scanner(System.in);int n =

11、0;System, out .printIn (”请输入要排序的数组个数”);n = in.nextlnt ();int a = new int n;for (int i = 0; i a.length; i+) n = in.nextInt ();a i = n;)for (int i = 1; i a.length; i+) for (int j = 0; j aj+l ) int b;b = a j ;aj = aj+1;aj+1 = b; )for (int i = 0; i a.length; i+) System.out.printIn (a i + ” n);扩展题目：访问中国空

12、气质量在线监测分析平台：https:分析自己家乡2020年空气质量AQ工的平均值。源程序：public class济南空气质量static double qiuhe (double b) / 数组值的合double sum = 0;for (int i = 0; i b.length; i+)returnsum = sum + bi; sum;static double double mean = returnstatic double double mean = returnpingjunzhi(double b) mean = 0;qiuhe (b) / b.length;mean;/总体

13、方差 static double doublefangcha(double b) fangcha = 0;for (int i = 0; i b.length; i+) fangcha = fangcha + (Math.pow(bi - pingjunzhi (b), 2);)fangcha = fangcha / (b.length - 1); return fangcha;public static void main(String args) / TODO自动生成的方法存根 int e = 2019, 2020, 2021 );double 114 );/ 2019double116

14、;/ 2020double82 );/ 2021double a = 132, 125,92, 92, 102, 143, 120, 75, 104,b = 141, 77, 78, 85, 101, 123, 96, 81, 92,c = 122, 75, 135, 90, 114, 122, 79, 99, 73,d = a, b, c ;87,79,73,96,89,82,for (int i = 0; i d.length; i+) if (pingjunzhi(di ) = 50) System.out.printin(ei System.out.printin(ei fangcha

15、(di);System.out.printin(ei pingjunzhi(di); else if (pingjunzhi(di) = System.out.printin(ei System.out.printin(ei fangcha(di);System.out.printin (e i pingj unzhi(di); else if (pingjunzhi(di) = System.out.printin(ei System.out.printin(ei fangcha(di);System.out.printin(ei pingjunzhi(di); else if (pingj

16、unzhi(di) = System.out.printin(ei System.out.printin(ei fangcha(di);System.out.printin(ei pingj unzhi(di); else if (pingjunzhi(di) = System.out.printin(ei System.out.printin(ei fangcha(di);System.out.printin(ei pingjunzhi(di); else System.out.printin(ei System.out.printin(ei fangcha(di);System.out.p

17、rintin(ei pingjunzhi(di);+ ”年空气质量是优”）；+ “年方差是“ + ”年平均均数是“ +100） （+ ”年空气质量是良”）；+ “年方差是“ + ”年平均均数是“ +150） + ”年空气质量是轻度污染”）；+ “年方差是“ + ”年平均均数是“ +200） + ”年空气质量是中度污染”）；+ “年方差是“ + ”年平均均数是“ +300） + ”年空气质量是重度污染”）；+ “年方差是“ + ”年平均均数是“ + ”年空气质量是优”）；+ “年方差是“ + ”年平均均数是“ +100） （+ ”年空气质量是良”）；+ “年方差是“ + ”年平均均数是“ +15

18、0） + ”年空气质量是轻度污染”）；+ “年方差是“ + ”年平均均数是“ +200） + ”年空气质量是中度污染”）；+ “年方差是“ + ”年平均均数是“ +300） + ”年空气质量是重度污染”）；+ “年方差是“ + ”年平均均数是“ + ”年空气质量是严重污染”）；+ “年方差是“ + ”年平均均数是“ +public class 方差!static double qiuhe (double b) / 数组值的合double sum = 0;for (int i = 0; i b.length; i+) sum = sum + bi;return sum;static double

19、 pingjunzhi (double b) / 平均值 double mean = 0;mean = qiuhe(b) / b.length;return mean;/总体方差static double fangcha(double b) double fangcha = 0;for (int i = 0; i b.length; i+) fangcha = fangcha + (Math.pow ( (bi - pingjunzhi (b)r 2); ) fangcha = fangcha / b.length; return fangcha;/总体标准差static double bia

20、ozhuncha(double b) doubl biaozhuncha;biaozhuncha = Math.sqrt(fangcha(b);return biaozhuncha; )/样本方差static double yangbenfangcha(double b) double yangbenfangcha = 0;for (int i = 0; i b.length; i+) yangbenfangcha = yangbenfangcha + (Math.pow(bi - pingjunzhi(b), 2);)yangbenfangcha = yangbenfangcha / (b.

21、length - 1);return yangbenfangcha;)/样本标准差static doubl yangbenbiaozhuncha(double data) double yangbenfangcha;yangbenfangcha = Math.sqrt(yangbenfangcha(data);return yangbenfangcha;public static void main(String args) Scanner in = new Scanner(System.in); double b = new double100; double n;for (int i = 0; i 100; i+) n = in.nextDouble (); if (n != -1) b i = n;三、实验总结