c++用switch语句设计一个选择式菜单，编写链式栈进栈、出栈、显示栈中全部元素，将一个正整数n转换成R进制，要求用顺序栈的来实现。

这是一个比较基础的编程题，下面是代码示例：

#include <iostream>
using namespace std;

struct Node {
    int data;
    Node* next;
};

class Stack {
public:
    Stack() {
        top = NULL;
    }

    void push(int val) {
        Node* newNode = new Node;
        newNode->data = val;
        newNode->next = top;
        top = newNode;
    }

    int pop() {
        if (top == NULL) {
            return -1;
        }
        Node* temp = top;
        int val = top->data;
        top = top->next;
        delete temp;
        return val;
    }

    void display() {
        Node* curr = top;
        while (curr != NULL) {
            cout << curr->data << " ";
            curr = curr->next;
        }
        cout << endl;
    }

private:
    Node* top;
};

int main() {
    int choice, n, r;
    Stack s;
    do {
        cout << "1. Push element" << endl;
        cout << "2. Pop element" << endl;
        cout << "3. Display stack" << endl;
        cout << "4. Convert to R-base" << endl;
        cout << "0. Exit" << endl;
        cout << "Enter your choice: ";
        cin >> choice;
        
        switch (choice) {
            case 1:
                int val;
                cout << "Enter value to push: ";
                cin >> val;
                s.push(val);
                break;
            case 2:
                int popVal;
                popVal = s.pop();
                if (popVal == -1) {
                    cout << "Stack is empty" << endl;
                } else {
                    cout << "Popped value is: " << popVal << endl;
                }
                break;
            case 3:
                s.display();
                break;
            case 4:
                cout << "Enter number to convert: ";
                cin >> n;
                cout << "Enter base of conversion: ";
                cin >> r;
                if (r < 2 || r > 16) {
                    cout << "Invalid base" << endl;
                } else {
                    Stack result;
                    while (n > 0) {
                        int rem = n % r;
                        n /= r;
                        result.push(rem);
                    }
                    cout << "Result: ";
                    result.display();
                }
                break;
            case 0:
                cout << "Exiting program..." << endl;
                break;
            default:
                cout << "Invalid choice" << endl;
        }
    } while (choice != 0);

    return 0;
}

这段代码中，我们通过一个 `Stack` 类来实现链式栈的进栈、出栈和显示栈中全部元素。在主函数中，我们通过一个 `switch` 语句来实现选择式菜单，用户可以通过输入数字来选择相应的操作。其中，第四个选项可以将一个正整数转换成任意进制，我们通过一个新的 `Stack` 对象来存储转换后的结果，并将结果输出到控制台。