java数组、链表实现栈

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话不多说，直接上代码：

定义一个通用的接口：

public interface MyStack <T>
{
   boolean isEmpty();    //判断是否为空
   int getLength();      //获得长度
   void clear();         //清空
   T pop();
   boolean push(T data);
}

一、数组实现栈：
public class MyArrStack<T> implements MyStack<T>
{
   private Object[] objs = new Object[5];
    private int size = 0;
   @Override
   public boolean isEmpty()
   {
       // TODO Auto-generated method stub
       return size==0;


   }

   @Override
   public int getLength()
   {
       // TODO Auto-generated method stub
       return size;
   }

   @Override
   public void clear()
   {
       // TODO Auto-generated method stub
       for(int i=0;i<size;i++)
       {
           objs[i]=null;
       }
       size=0;
   }

   @Override
   public T pop()
   {
       // TODO Auto-generated method stub
       if(size==0)
       {
       return null;
       }
       else
       return (T)objs[--size];

   }

   @Override
   public boolean push(T data)
   {
       // TODO Auto-generated method stub

       if(size>=objs.length)
       {
           //System.out.println("数组已满");
           Object[] tmp=new Object[objs.length*3/2+1];
           for(int i=0;i<size;i++)
           {
               tmp[i]=objs[i];
               objs[i]=null;
           }
           objs=tmp;

       }
       objs[size++]=data;
       return true;
   }
public static void main(String[] args)
{
   MyStack<Integer> st = new MyArrStack<Integer>();
   int[] num={1,2,3,5,8,9,6};
   for(int i=0;i<num.length;i++)
   {
       st.push(num[i]);
   }
   System.out.println("栈中有"+st.getLength()+"个数");
   while(!st.isEmpty())
   {
   System.out.println(st.pop());
   }
}
}
二、链表实现栈：

public class MyLinkedStack<T> implements MyStack<T>
{
    private Node top;
    private int size;
    public MyLinkedStack()
    {
       top=null;
       size=0;
    }
   @Override
   public boolean isEmpty()
   {
       // TODO Auto-generated method stub

       return size==0;
   }

   @Override
   public int getLength()
   {
       // TODO Auto-generated method stub
       return size;
   }

   @Override
   public void clear()
   {
       // TODO Auto-generated method stub
        top=null;
        size=0;
   }

   @Override
   public T pop()
   {
       // TODO Auto-generated method stub
       if (top != null) {
            Node node = top;
            // 改变栈顶指针
            top = top.pre;
            size--;
            return node.data;
        }

       return null;
   }

   @Override
   public boolean push(T data)
   {
       // TODO Auto-generated method stub
       Node node=new Node();
       node.data=data;
       node.pre=top;
       top=node;
       size++;
       return true;
   }
   private final class Node
   {
        private Node pre;
        private T data;
    }
   public static void main(String[] args)
   {
       int[] num={5,2,1,7,9,6,3};
       MyStack<Integer> st=new MyLinkedStack<Integer>();
       for(int i=0;i<num.length;i++)
       {
           st.push(num[i]);
       }
       System.out.println("栈的长度为："+st.getLength());
       while(!st.isEmpty())
       {
           System.out.println(st.pop());
       }
   }
}