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：

class ArrayApp
   {
   public static void main(String[] args)
      {
      long[] arr;                  //声明数组
      arr = new long[100];         // 创建数组
      int nElems = 0;              // 索引
      int j;                       // 循环变量
      long searchKey;              //关键字
//--------------------------------------------------------------
      arr[0] = 77;                 //插入十项
      arr[1] = 99;
      arr[2] = 44;
      arr[3] = 55;
      arr[4] = 22;
      arr[5] = 88;
      arr[6] = 11;
      arr[7] = 00;
      arr[8] = 66;
      arr[9] = 33;
      nElems = 10;                 // 索引值为10
//--------------------------------------------------------------
      for(j=0; j<nElems; j++)      // 遍历数组
         System.out.print(arr[j] + " ");
      System.out.println("");
//--------------------------------------------------------------
      searchKey = 66;              //查找值为 66
      for(j=0; j<nElems; j++)        
         if(arr[j] == searchKey)      
            break;                   
      if(j == nElems)                 
         System.out.println("Can't find " + searchKey);
      else
         System.out.println("Found " + searchKey);     
//--------------------------------------------------------------
      searchKey = 55;              //删除55
      for(j=0; j<nElems; j++)           
      if(arr[j] == searchKey)
         break;
      for(int k=j; k<nElems; k++)       
         arr[k] = arr[k+1];
      nElems--;                      
//--------------------------------------------------------------
      for(j=0; j<nElems; j++)     
         System.out.print( arr[j] + " ");
      System.out.println("");
      }  
   }  

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

class LowArray
   {
   private long[] a;                 // ref to array a
//--------------------------------------------------------------
   public LowArray(int size)         // constructor
      { a = new long[size]; }        // create array
//--------------------------------------------------------------
   public void setElem(int index, long value)  // set value
      { a[index] = value; }
//--------------------------------------------------------------
   public long getElem(int index)              // get value
      { return a[index]; }
//--------------------------------------------------------------
   } 
////////////////////////////////////////////////////////////////
class LowArrayApp
   {
   public static void main(String[] args)
      {
      LowArray arr;                 // reference
      arr = new LowArray(100);      // create LowArray object
      int nElems = 0;               // number of items in array
      int j;                        // loop variable

      arr.setElem(0, 77);           // insert 10 items
      arr.setElem(1, 99);
      arr.setElem(2, 44);
      arr.setElem(3, 55);
      arr.setElem(4, 22);
      arr.setElem(5, 88);
      arr.setElem(6, 11);
      arr.setElem(7, 00);
      arr.setElem(8, 66);
      arr.setElem(9, 33);
      nElems = 10;                 // now 10 items in array

      for(j=0; j<nElems; j++)      // display items
         System.out.print(arr.getElem(j) + " ");
      System.out.println("");

      int searchKey = 26;          // search for data item
      for(j=0; j<nElems; j++)            // for each element,
         if(arr.getElem(j) == searchKey) // found item?
            break;
      if(j == nElems)                    // no
         System.out.println("Can't find " + searchKey);
      else                               // yes
         System.out.println("Found " + searchKey);

                                   // delete value 55
      for(j=0; j<nElems; j++)            // look for it
      if(arr.getElem(j) == 55)
         break;
      for(int k=j; k<nElems; k++)        // higher ones down
         arr.setElem(k, arr.getElem(k+1) );
      nElems--;                          // decrement size

      for(j=0; j<nElems; j++)      // display items
         System.out.print( arr.getElem(j) + " ");
      System.out.println("");
      }  // end main()
   }  // end class LowArrayApp

大家试一下运行的效果是不是一样的