第2次作业（个人项目实践）

1. 设计一个类（不妨叫做A ），实现对一维数组的指定范围内的元素相加运算。

 1   package yang;
 2   
 3   import java.util.Scanner;//用scanner类从键盘输入数据
 4  
 5       public class yy {
 6       public static void main(String[]args){
 7           
 8       int[] aa={-2574,-4010,8243,771,2447,-5197,2556,8044,3314,3617,6065,-2817,3131,6318,2186,-113,629,-2582,-37,-1520,164,2055,-5936,5912,1717,5988,4781,5757,892,-4394,8034,2213,-1080,-2080,5364,106,2657,566,3940,-5116,4583,1806,6555,2621,-7197,528,1626,18,1049,6243,3198,4397,-1325,9087,936,-6291,662,-178,135,-3473,-2385,-165,1713,-7949,-4234,1138,2212,104,6968,-3632,3801,1137,-1296,-1215,4272,6223,-5922,-7723,7044,-2938,-8180,1356,1159,-4022,-3713,1158,-8715,-4081,-2541,-2555,-2284,461,940,6604,-3631,3802,-2037,-4354,-1213,767};
 9           
10             int sum=0;//用于统计和
11               Scanner a = new Scanner(System.in);  //定义类的对象a,接收来自键盘的数据                            
12               System.out.println("从何开始？：");
13           int start = a.nextInt() ;
14               System.out.println("到哪结束？：");
15           int end =a.nextInt();
16               System.out.println("指定范围是:"+start+"---"+end);
17     for(int i=start-1;i<=end-1;i++)
18             sum+=aa[i];//此处循环
19             System.out.println("运算和:");
20             System.out.println(sum);
21  }
22   }

运算结果为：

2. 设计一个类（不妨叫做B ），实现对二维数组的指定范围内的元素相加运算。

 1 package yang;
 2 import java.util.Scanner;
 3 public class yy2 {
 4     public static void main(String[] args) {
 5        int[][] b={
 6                       { -2574,-4010,8243,771,2447,-5197,2556,8044,3314,3617,6065,-2817,3131,6318,2186,-113,629,-2582,-37,-1520,
 7                         164,2055,-5936,5912,1717,5988,4781,5757,892,-4394,8034,2213,-1080,-2080,5364,106,2657,566,3940,-5116,
 8                         4583,1806,6555,2621,-7197,528,1626,18,1049,6243,3198,4397,-1325,9087,936,-6291,662,-178,135,-3473,-2385,
 9                        -165,1713,-7949,-4234,1138,2212,104,6968,-3632,3801,1137,-1296,-1215,4272,6223,-5922,-7723,7044,-2938,-8180,
10                        1356,1159,-4022,-3713,1158,-8715,-4081,-2541,-2555,-2284,461,940,6604,-3631,3802,-2037,-4354,-1213,767},
11                       { 2740,-4182,-5632,-2966,-1953,567,-8570,1046,2211,1572,-2503,-1899,3183,-6187,3330,3492,-464,-2104,316,8136,
12                         470,50,466,-1424,5809,2131,6418,-3018,6002,-8379,1433,1144,2124,1624,-602,-5518,5872,870,-5175,-3961,-427,
13                        -6284,2850,481,6175,141,-766,-1897,-748,-4248,366,4823,3003,1778,3256,2182,2253,5076,5540,-2650,2451,-1875,
14                       5482,-6881,-329,-969,-8032,-2093,612,1524,-5492,5758,-7401,-5039,3241,6338,3581,4321,-1072,4942,2131,210,-7045,
15                       -7514,7450,-1142,-2666,-4485,-639,2121,-5298,-3805,-1686,-2520,-1680,2321,-4617,-1961,2076,7309}
16                      };
17          
18           Scanner b1 = new Scanner(System.in);
19           System.out.println("横轴开始:");//把二维数组看做一个数轴
20             int startA = b1.nextInt(); 
21           System.out.println("横轴结束:");
22             int endA =b1.nextInt();
23           System.out.println("竖轴开始:");
24             int startD = b1.nextInt(); 
25           System.out.println("数轴结束:");
26             int endD =b1.nextInt();
27           System.out.println("指定范围为：");
28           System.out.println("横轴"+startA+"---"+endA);
29           System.out.println("竖轴"+startD+"---"+endD);
30          
31          int j=startD-1;
32          int sum=0;
33          for(int i=startA-1;i<endA-1; i++) //利用for while循环嵌套语句求和
34          {  
35              while(j<endD-1)
36              {
37                  j++;
38                  sum=sum+b[i][j];  
39              }
40          }        
41                
42           System.out.println("总和:"+sum);
43 
44       }
45  }

运算结果为：

            这次作业做的可以算是历经沧桑_(:зゝ∠)_，数组 虽然以前学过，但也就是一个模糊的概念，也没有想要把它明了话，但是如今为了把作业写好，来来回回把书翻了好几遍，还去问了已经做好的同学，如果以前学习我也能有这态度，说不定现在编写代码就没有这么痛苦了。不过也因为这次作业，让我学到了许多知识，像利用scanner类接收从键盘输入的信息。scanner类不仅可以从键盘读取数据，还可以从其他数据源读取。在这次的代码编写中，我发现我很容易就会漏掉大括号，分号等等一些细小的问题，往往因为这些问题导致代码出现大部分错误，还常常找不出错误原因_(:зゝ∠)_，一行行代码找下来，发现因为漏掉小符号，就想说自己真的粗心的可以。

            我觉得我的代码还是存在很多的问题，一维二维勉强写出来了，但是三维数组的编写感觉有点力不从心了，错误多，而且经常改掉这个错误就又会出现新的错误，有几次修改后没有报错了，一运行编译器就报错了，因为没有运行出结果，我就没把三维数组的代码贴上来，我会在之后再研究研究，把代码完善并且运行出来后，再发表随笔将他发布出来。然后，学习真的是要不停复习复习复习，因为一段时间不看，很多东西就会忘掉_(:зゝ∠)_。我会在接下来的时间好好学习，在学习新内容的同时复习以前学习过的知识！完善自己！(๑•̀ㅂ•́)و✧