java 数组扩容

 /**

 *数组的扩容

 *往数组里面加东西,数组满了,大小加倍
 */
public class ExpandArray{
 private int[] arrays = new int[10];
 private int index = 0;
 
 public void show(){ 
  System.out.println(arrays.length);
  //扩容
  for(index = 0;index<30;index++){
   if(index==arrays.length){
    this.expand();
    System.out.println(index+" "+arrays.length);
    for(int i = 0;i < index;i++)
     System.out.print(arrays[i]+" ");
    System.out.println();
   }
   arrays[index] = index;
  }
 }

 public void expand(){
  int[] arrays2 = new int[arrays.length*2];
  System.arraycopy(arrays, 0, arrays2, 0, arrays.length);
  arrays = arrays2;
 }
 
 public static void main(String[] args) {
  ExpandArray ea = new ExpandArray();
  ea.show();
 }
}