class Node
{ int a;
public Node(int a)
{ this.a=a; }
public int A
{ get{return a;} set{a=value;} }
public Node next;
}
class LinkedList
{ protected Node header;
public void Generate(int x)
{ if(header==null)
header=new Node(x);
else
{ Node n = new Node(x);
n.next=header;
header=n;
}
}
public void Out()
{ Node tmp=header;
while(tmp!=null)
{ Console.WriteLine(tmp.A);
tmp = tmp.next;
} } }
class Stack : LinkedList
{ public void Push(int x)
{ this.Generate(x); }
public int Pop()
{ if(this.header == null)
return -1; // empty stack
int n = header.A;
header = header.next;
return n;
}
}
class Test
{ static void Main()
{ Stack ss = new Stack();
ss.Push(7);
ss.Push(78);
ss.Push(9);
ss.Push(2);
int i = ss.Pop();
while(i != -1)
{ Console.WriteLine(i);
i = ss.Pop();
} } } }