第二次作业（上）：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。 

package zwei;
import java.util.Scanner;//因为等下要从键盘输入数据
public class A {
public static void main(String[]args)
{
int[] arr1={-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};
int sum=0;//用于统计和
Scanner se = new Scanner(System.in);            
System.out.println("从第几个开始加？：");
int start = se.nextInt() ;
System.out.println("加到第几个为止？：");
int end =se.nextInt();
System.out.println("指定范围是");
System.out.println("第"+start+"个元素到第"+end+"个元素");
for(int i=start-1;i<=end-1;i++)//我希望在编程之外可以直观一点，不要整天从零计数
sum+=arr1[i];//于此处循环
System.out.println("相加运算:");
System.out.println(sum);
}
}

以上类即可实现对一维数组的指定范围内的元素相加。

运行结果图：

  

 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。 

package zwei;
import java.util.Scanner;
public class B {
public static void main(String[]args){
int[][] a={{-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},{2740,-4182,-5632,-2966,-1953,567,-8570,1046,2211,1572,-2503,-1899,3183,-6187,3330,3492,-464,-2104,316,8136,470,50,466,-1424,5809,2131,6418,-3018,6002,-8379,1433,1144,2124,1624,-602,-5518,5872,870,-5175,-3961,-427,-6284,2850,481,6175,141,-766,-1897,-748,-4248,366,4823,3003,1778,3256,2182,2253,5076,5540,-2650,2451,-1875,5482,-6881,-329,-969,-8032,-2093,612,1524,-5492,5758,-7401,-5039,3241,6338,3581,4321,-1072,4942,2131,210,-7045,-7514,7450,-1142,-2666,-4485,-639,2121,-5298,-3805,-1686,-2520,-1680,2321,-4617,-1961,2076,7309}};
int sum=0;
Scanner se = new Scanner(System.in);
System.out.println("从第几行开始？");//由于给出的数据原因，一共两行
int startH = se.nextInt(); 
System.out.println("到第几行为止？");
int endH =se.nextInt();
System.out.println("从第几列开始？");//最多100列
int startL = se.nextInt(); 
System.out.println("到第几列为止？");
int endL =se.nextInt();
System.out.println("指定的范围是");
System.out.println("第"+startH+"行第"+startL+"列 到 第"+endH+"行第"+endL+"列");
for(int i=startH-1;i<=endH-1;i++)
{
    for(int j=startL-1;j<=endL-1;j++)
    {
    sum+=a[i][j];
    }
}
System.out.println(sum);  
}
}

 以上类即可实现对二维数组的指定范围内的元素相加。

运行结果图：

3. 设计一个类（不妨叫做C ），实现对三维数组的指定范围内的元素相加运算。  

package zwei;
import java.util.Scanner;
public class C {
public static void main(String[]args)
{
int sum=0;
int[][][] a = new int[][][]
{
{{-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}},
{{2740,-4182,-5632,-2966,-1953,567,-8570,1046,2211,1572,-2503,-1899,3183,-6187,3330,3492,-464,-2104,316,8136,470,50,466,-1424,5809,2131,6418,-3018,6002,-8379,1433,1144,2124,1624,-602,-5518,5872,870,-5175,-3961,-427,-6284,2850,481,6175,141,-766,-1897,-748,-4248,366,4823,3003,1778,3256,2182,2253,5076,5540,-2650,2451,-1875,5482,-6881,-329,-969,-8032,-2093,612,1524,-5492,5758,-7401,-5039,3241,6338,3581,4321,-1072,4942,2131,210,-7045,-7514,7450,-1142,-2666,-4485,-639,2121,-5298,-3805,-1686,-2520,-1680,2321,-4617,-1961,2076,7309}},
{{302,-7944,-6551,6648,-884,-6332,1188,-248,3902,-2171,-3782,-3510,6203,-636,-4605,4497,3187,-6278,1198,-7963,7647,-3022,-8267,7995,-1998,-4171,730,-8117,-1706,7601,-2454,-6161,-1810,243,-2841,-5377,2985,2328,177,5622,3596,3057,2830,-1151,6566,2254,6972,-3060,4063,367,84,3156,3880,-1530,5272,1385,-565,-1736,1267,-3863,-229,2072,2423,-7449,9555,2844,-1278,-3613,-919,4153,-4232,4032,-5732,199,4792,2498,-3344,-4193,2650,-579,3416,-3575,1822,-6936,-2661,-1873,414,2314,6844,7613,-7844,6680,5974,2208,-3597,6302,4396,-141,-1864,1939}}
};//这边的三位数组定义是宝玉老师给的建议，看起来比较抽象，因为是y=0的三维数组。
Scanner se = new Scanner(System.in) ;
System.out.println("横坐标从几开始？");//1～3
int startH = se.nextInt() ;
System.out.println("横坐标到几为止？");
int endH =se.nextInt();
System.out.println("纵坐标从几开始？");//1～100
int startZ = se.nextInt() ;
System.out.println("纵坐标到几为止？");
int endZ =se.nextInt();
System.out.println("垂直轴从几开始？");//只有1
int startC = se.nextInt() ;
System.out.println("垂直轴到几为止？");
int endC =se.nextInt();

for(int i=startH-1;i<=endH-1;i++)
{
for(int j=startC-1;j<=endC-1;j++)
{
for(int q=startZ-1;q<=endZ-1;q++)
{
sum+=a[i][j][q];
}
}
}
System.out.println(sum);
}
}

 以上类即可实现对三维数组的指定范围内的元素相加。

运行结果图：

 4.总结：

     基本是一个赶工之作，还有非常多需要改进的地方，比如输入数据过大的时候程序并不能判断，只会丢出个错误结果，没有数据溢出的检测机制。但至少很多由于给出数组的原因被定死在0的变量，还是按照可自行选择的方式给出了范围的选择，即使以后给出的数组范围扩充得再大，也可以将这次编程的成果直接套用了，自认为普适性还是蛮高的。编程主要是for语句的循环嵌套，一、二、三维数组的初始化还有Scanner类的nextInt()方法，本来最难的部分——编程读取excel，被我用word的操作技巧给避开了。为了完成下一次的作业的话，要马上去复习类的封装继承了。

      在程序上出现错误时，通常都会先删除无关与必定正确的代码，专心于剩下的部分寻找出错点，也常常会绕一个大圈子回到原点，最后删除多余的部分结局豁然开朗

      还有一个比较印象深刻的问题，在初次尝试书写三维数组的时候，即是编译器没有给出任何警告和错误，在MyEclipse中也是无论怎样调试都无法输出结果，感觉不知所措，惊呼三维数组不可战胜！睡了一觉起来才发现，是运行方式没有选择java应用程序，用了一个类似临时服务器的方法运行。之后的过程就非常的顺畅了，也在不长的时间内理解了三维数组的构造。当然也少不了助教在QQ群里对我提出问题的解答，最后的三位数组初始化形式也是在助教老师的点拨之下想出来的。

      这次完成作业的过程中有很多地方，都是在和林杰同学提出一些设想后，由他来完成初步测试版本，细节上共同讨论和完善然后得出结果。在此表示感谢！