数据结构(Java ArrayList模拟)本代码重在学习数据结构思路，代码完整性欠缺，请见谅

ArrayList的核心是以动态数组为存储结构。

class ArrayList<T>{
 private int capability ;
 private static final int defaultCapability = 8;
 private int size = 0;
 private Object[] array = null;
 public ArrayList(final int n){
  this.capability = n;
     this.array = new Object[capability];
 }
 public ArrayList(){
    this.capability = defaultCapability;
    this.array = new Object[capability];
 }
 //添加数据
 public void add(T data){
  Object obj = (Object)data;
  resizeArray();
  array[size] = data;
  size++;
  
 }
 public int size(){
  return size;
 }
 public T get(int index){
  if( index < 0 ||  index >= size)
   return null;
  return (T)array[index];
 }
 public T remove(int index){
  T t = get(index);
  if( t != null ){
   
   for(int i = index; i < size-1; i++){
    array[i] = array[i+1];
   }
   size --;
  }
  return t;
 }
 //当数据量为总容量的75%时重新设置数组的大小
 private void resizeArray(){
  if(size*4 > capability*3 ){
   capability = capability *2;
   Object[] result = new Object[capability];
   System.arraycopy(array, 0, result, 0, size);
   array = result;
  }
 }
}
public class ArrayListTest {
 public static void main(String[] args) {
  ArrayList<String> arrays = new ArrayList<String>();
  arrays.add("123");
  arrays.add("124");
  arrays.add("125");
  arrays.remove(1);
  //System.out.println(arrays.get(4));
  for(int i =0 ;i< arrays.size(); i++)
   System.out.println(arrays.get(i));
 }

}