[whiteship스터디 4주차 과제]ListNode클래스를 이용해 Stack구현

과제 4. 앞서 만든 ListNode를 사용해서 Stack을 구현하세요.

• ListNode head를 가지고 있는 ListNodeStack 클래스를 구현하세요.
• void push(int data)를 구현하세요.
• int pop()을 구현하세요.

---

package Week4_Stack_ListNode;

public class ListNode {
    public int data;
    public ListNode next;

    ListNode(){
        this.data = 0;
        this.next=null;
    }
}

 

package Week4_Stack_ListNode;


public class Stack {
    public ListNode head;
    public int size = 0;

    public void push(int data) {
        ListNode node = new ListNode();
        node.data = data;
        if (head == null) {
            head = node;
            size = 1;
            return;
        }
        ListNode temp = head;
        for (int i = 1; i < size; i++) {
            temp = temp.next;
        }
        temp.next = node;
        size++;
    }

    public int pop() {
        if (head == null || size == 0) {
            System.out.println("스택이 비어있습니다.");
            return -1;
        }
        ListNode temp = head;
        for (int i = 1; i < size; i++) {
            temp = temp.next;
        }
        int data = temp.data;
        size--;
        temp = null;
        return data;
    }

    public void stackList() {
        if (head == null || size == 0) {
            System.out.println("스택이 비어있습니다.");
            return;
        }
        ListNode temp = head;
        for (int i = 0; i < size; i++) {
            System.out.print("|");
            System.out.print(temp.data);
            temp = temp.next;
        }
        System.out.println("|");
    }

    public int getSize() {
        return this.size;
    }
}

package Week4_Stack_ListNode;

public class Test {
    public static void main(String[] args) {
        Stack stack = new Stack();
        stack.push(1);
        stack.push(2);
        stack.push(3);
        stack.push(4);

        System.out.println("스택 리스트 출력");
        stack.stackList();

        System.out.println("Pop Item = " + stack.pop());
        System.out.println("Pop Item = " + stack.pop());
        System.out.println("Pop Item = " + stack.pop());
        System.out.println("Pop Item = " + stack.pop());
        System.out.println(stack.pop());

        System.out.println(stack.size);
    }
}