（2）栈的链式实现：建立一个链栈，依次将a,b,c,d入栈；出栈并输出出栈结点数据域的值；将f入栈；输出当前链栈中各结点的数据域的值；用c++写代码

好的，以下是栈的链式实现的代码：

#include <iostream>
using namespace std;

class Node {
public:
    char data;
    Node* next;

    Node(char element) {
        data = element;
        next = nullptr;
    }
};

class Stack {
private:
    Node* top;
public:
    Stack() {
        top = nullptr;
    }

    bool isEmpty() {
        return top == nullptr;
    }

    void push(char element) {
        Node* newNode = new Node(element);
        newNode->next = top;
        top = newNode;
    }

    char pop() {
        if (isEmpty()) {
            cout << "Stack is empty. Cannot pop element." << endl;
            return '\0';
        }
        char poppedElement = top->data;
        Node* temp = top;
        top = top->next;
        delete temp;
        return poppedElement;
    }

    void display() {
        cout << "Stack elements: ";
        Node* temp = top;
        while (temp != nullptr) {
            cout << temp->data << " ";
            temp = temp->next;
        }
        cout << endl;
    }
};

int main() {
    Stack stack;

    stack.push('a');
    stack.push('b');
    stack.push('c');
    stack.push('d');

    cout << "Popped element: " << stack.pop() << endl;

    stack.push('f');

    stack.display();

    return 0;
}

输出结果为：

Popped element: d
Stack elements: f c b a

希望对你有所帮助！如果还有其他问题，请随时提问。