public class Entry<T> {
private T value;
private Entry<T> next;
public Entry() {
  this(null);
}
public Entry(T value) {
  this.value=value;
  this.next=null;
}
  
public void setValue(T value) {
  this.value=value;
}

public void setNext(Entry<T> next) {
  this.next=next;
}

public T getValue() {
  return value;
}

public Entry<T> getNext(){
  return next;
}

}

public class Link<T> {//鏈表實現(xiàn)棧,先進(jìn)后出
private Entry<T> headEntry;
private int size=0;
public Link() {
  headEntry =new Entry<>();
}
public void pop() {//出棧
  if(headEntry.getNext()!=null) {
  headEntry.getNext().setValue(null);
  headEntry.setNext(headEntry.getNext().getNext());
  size--;
  }else {
    return;
  }
  
}
public void push(T value) {//入棧
  Entry<T> newEntry=new Entry<>(value);
  if(headEntry.getNext()!=null) {
    newEntry.setNext(headEntry.getNext());
    
  }
    headEntry.setNext(newEntry);
    size++;
  
}


public void show(){//打印節(jié)點
  if(headEntry.getNext()==null) {
    return;
  }
  for(Entry<T> p = headEntry.getNext();p!=null;p=p.getNext()){
    System.out.print(p.getValue()+" ");
  }
  System.out.println();
}
}

public class Main {
public static void main(String args[]) {
  Link<String> ll=new Link<>();
  ll.push("1");//入棧
  ll.push("2");
  ll.push("3");
  ll.push("4");
  ll.push("5");
  ll.push("6");
  ll.push("7");
  ll.push("8");
  ll.show();//打印棧內(nèi)元素
  ll.pop();//彈出棧頂元素
  ll.show();
  ll.pop();
  ll.show();
}
}