IT실전교육,탑크리에듀교육센터: 자바 연결리스트로 구현한 스택(Java Linkked List Stack) 소스 입니다.

2014년 2월 5일 수요일

자바 연결리스트로 구현한 스택(Java Linkked List Stack) 소스 입니다.

interface Stack {
            public boolean isEmpty();
            public Object peek();
            public void push(Object theObject);
            public Object pop();
}

class ChainNode {
          Object element;
          ChainNode next;
          ChainNode() {}
          ChainNode(Object element) { this.element = element;}
          ChainNode(Object element, ChainNode next) {
    this.element = element;   this.next = next;
     }
}

public class LinkedStack implements Stack {
protected ChainNode topNode;

     public LinkedStack() {
  topNode = new ChainNode();
}

public boolean isEmpty() {
  return topNode.next == null;
}

public Object peek() {
if (isEmpty()) throw new EmptyStackException();
return topNode.next.element;
}

public void push(Object theElement) {
  ChainNode p = new ChainNode(theElement, null);
  p.next = topNode.next;
  topNode.next = p;
}

public Object pop() {
    if (isEmpty())    throw new EmptyStackException();
    Object topElement = topNode.next.element;
    topNode.next = topNode.next.next;
    return topElement;
}

public String toString() {
   StringBuffer sb = new StringBuffer("[");
   ChainNode p = topNode.next;
   do {
    if (p.element == null) sb.append("null");
    else sb.append(p.element.toString());
    p = p.next;
    if (p != null) sb.append(",");
   } while (p != null);
   sb.append("]");
   return sb.toString();
}
}

public class EmptyStackException extends RuntimeException {
   public EmptyStackException()   {
      super ("The stack is empty.");
   }

   public EmptyStackException (String message)   {
      super (message);
   }
}

public class Main {
public static void main(String args[]) {
      LinkedStack myStack = new LinkedStack();
      myStack.push("a");
      myStack.push("b");
      myStack.push("c");
   System.out.println(myStack);
   myStack.pop();
   System.out.println(myStack);
   System.out.print("현재 top pointer의 data : ");
   System.out.println(myStack.peek());
}
}

[출처] 오라클자바커뮤니티 - http://www.oraclejavanew.kr/bbs/board.php?bo_table=LecJavaAlgorithm&wr_id=87