数组举例
这个例子是用面向过程的编写，然后再介绍一个可达到同样效果的面向对象的方法
array.java代码如下：
1 class ArrayApp 2 { 3 public static void main(String[] args) 4 { 5 long[] arr; //声明数组 6 arr = new long[100]; // 创建数组 7 int nElems = 0; // 索引 8 int j; // 循环变量 9 long searchKey; //关键字 10 //-------------------------------------------------------------- 11 arr[0] = 77; //插入十项 12 arr[1] = 99; 13 arr[2] = 44; 14 arr[3] = 55; 15 arr[4] = 22; 16 arr[5] = 88; 17 arr[6] = 11; 18 arr[7] = 00; 19 arr[8] = 66; 20 arr[9] = 33; 21 nElems = 10; // 索引值为10 22 //-------------------------------------------------------------- 23 for(j=0; j<nElems; j++) // 遍历数组 24 System.out.print(arr[j] + " "); 25 System.out.println(""); 26 //-------------------------------------------------------------- 27 searchKey = 66; //查找值为 66 28 for(j=0; j<nElems; j++) 29 if(arr[j] == searchKey) 30 break; 31 if(j == nElems) 32 System.out.println("Can't find " + searchKey); 33 else 34 System.out.println("Found " + searchKey); 35 //-------------------------------------------------------------- 36 searchKey = 55; //删除55 37 for(j=0; j<nElems; j++) 38 if(arr[j] == searchKey) 39 break; 40 for(int k=j; k<nElems; k++) 41 arr[k] = arr[k+1]; 42 nElems--; 43 //-------------------------------------------------------------- 44 for(j=0; j<nElems; j++) 45 System.out.print( arr[j] + " "); 46 System.out.println(""); 47 } 48 }
下面代码用面向对象的方法实现，看看这两者的区别
代码如下
1 class LowArray 2 { 3 private long[] a; // ref to array a 4 //-------------------------------------------------------------- 5 public LowArray(int size) // constructor 6 { a = new long[size]; } // create array 7 //-------------------------------------------------------------- 8 public void setElem(int index, long value) // set value 9 { a[index] = value; } 10 //-------------------------------------------------------------- 11 public long getElem(int index) // get value 12 { return a[index]; } 13 //-------------------------------------------------------------- 14 } 15 //////////////////////////////////////////////////////////////// 16 class LowArrayApp 17 { 18 public static void main(String[] args) 19 { 20 LowArray arr; // reference 21 arr = new LowArray(100); // create LowArray object 22 int nElems = 0; // number of items in array 23 int j; // loop variable 24 25 arr.setElem(0, 77); // insert 10 items 26 arr.setElem(1, 99); 27 arr.setElem(2, 44); 28 arr.setElem(3, 55); 29 arr.setElem(4, 22); 30 arr.setElem(5, 88); 31 arr.setElem(6, 11); 32 arr.setElem(7, 00); 33 arr.setElem(8, 66); 34 arr.setElem(9, 33); 35 nElems = 10; // now 10 items in array 36 37 for(j=0; j<nElems; j++) // display items 38 System.out.print(arr.getElem(j) + " "); 39 System.out.println(""); 40 41 int searchKey = 26; // search for data item 42 for(j=0; j<nElems; j++) // for each element, 43 if(arr.getElem(j) == searchKey) // found item? 44 break; 45 if(j == nElems) // no 46 System.out.println("Can't find " + searchKey); 47 else // yes 48 System.out.println("Found " + searchKey); 49 50 // delete value 55 51 for(j=0; j<nElems; j++) // look for it 52 if(arr.getElem(j) == 55) 53 break; 54 for(int k=j; k<nElems; k++) // higher ones down 55 arr.setElem(k, arr.getElem(k+1) ); 56 nElems--; // decrement size 57 58 for(j=0; j<nElems; j++) // display items 59 System.out.print( arr.getElem(j) + " "); 60 System.out.println(""); 61 } // end main() 62 } // end class LowArrayApp
大家试一下运行的效果是不是一样的
