栈的数组实现

1.首先定义了栈需要实现的接口

public interface Mystack<T> {

    boolean isempty();

   void clear();

   int length();
   //入栈
   boolean push(T data);
   //出栈
   T pop();
}

2.栈的数组实现

package suanfa;

public class MyArrayStack<T> implements Mystack<T> {

    private Object [] obs=new Object[16];
    private int size=0;

    @Override
    public boolean isempty() {
        // TODO Auto-generated method stub
        return size==0;
    }

    @Override
    public void clear() {
        // TODO Auto-generated method stub
        for (int i=0;i<obs.length;i++){

            obs[i]=null;
        }

        size=0;
    }

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

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

        if(size>=obs.length){
            resize();

        }
        obs[size++]=data;

        return true;

    }

    @Override
    public T pop() {
        // TODO Auto-generated method stub

if(size==0){
       return null;
       }
     return (T) obs[--size];

    }

    private void resize(){

        Object [] tmp=new Object[obs.length*3/2+1];

        for(int i=0;i<obs.length;i++){
            tmp[i]=obs[i];
            obs[i]=null;

        }

        obs=tmp;

    }

}