用c++编写一个停车场管理系统需要展现一个菜单界面，用户可以根据选项进入普通用户和管理员，用户界面普通用户只能查看汽车信息，只有管理员用户才能添加，修改，删除汽车信息，普通用户和管理员用户具备返回主菜单的功能

好的，以下是一个基本的停车场管理系统的 C++ 代码示例，包含了菜单界面、普通用户和管理员用户的功能。

#include <iostream>
#include <string>
#include <vector>

using namespace std;

struct Car {
    string plateNumber;
    string brand;
    string model;
};

vector<Car> cars;

void printMainMenu() {
    cout << "Welcome to Parking Lot Management System!" << endl;
    cout << "1. User Login" << endl;
    cout << "2. Admin Login" << endl;
    cout << "3. Exit" << endl;
    cout << "Please enter your choice: ";
}

void printUserMenu() {
    cout << "User Menu:" << endl;
    cout << "1. View Car Information" << endl;
    cout << "2. Main Menu" << endl;
    cout << "Please enter your choice: ";
}

void printAdminMenu() {
    cout << "Admin Menu:" << endl;
    cout << "1. Add Car Information" << endl;
    cout << "2. Modify Car Information" << endl;
    cout << "3. Delete Car Information" << endl;
    cout << "4. Main Menu" << endl;
    cout << "Please enter your choice: ";
}

void viewCarInfo() {
    cout << "Car Information:" << endl;
    for (int i = 0; i < cars.size(); i++) {
        cout << "Plate Number: " << cars[i].plateNumber << endl;
        cout << "Brand: " << cars[i].brand << endl;
        cout << "Model: " << cars[i].model << endl;
        cout << endl;
    }
}

void addCarInfo() {
    Car car;
    cout << "Enter Plate Number: ";
    cin >> car.plateNumber;
    cout << "Enter Brand: ";
    cin >> car.brand;
    cout << "Enter Model: ";
    cin >> car.model;
    cars.push_back(car);
    cout << "Car Information Added Successfully!" << endl;
}

void modifyCarInfo() {
    string plateNumber;
    cout << "Enter Plate Number to Modify: ";
    cin >> plateNumber;
    for (int i = 0; i < cars.size(); i++) {
        if (cars[i].plateNumber == plateNumber) {
            cout << "Enter New Brand: ";
            cin >> cars[i].brand;
            cout << "Enter New Model: ";
            cin >> cars[i].model;
            cout << "Car Information Modified Successfully!" << endl;
            return;
        }
    }
    cout << "Car Not Found!" << endl;
}

void deleteCarInfo() {
    string plateNumber;
    cout << "Enter Plate Number to Delete: ";
    cin >> plateNumber;
    for (int i = 0; i < cars.size(); i++) {
        if (cars[i].plateNumber == plateNumber) {
            cars.erase(cars.begin() + i);
            cout << "Car Information Deleted Successfully!" << endl;
            return;
        }
    }
    cout << "Car Not Found!" << endl;
}

int main() {
    int choice;
    do {
        printMainMenu();
        cin >> choice;
        switch (choice) {
            case 1: {
                int userChoice;
                do {
                    printUserMenu();
                    cin >> userChoice;
                    switch (userChoice) {
                        case 1:
                            viewCarInfo();
                            break;
                        case 2:
                            break;
                        default:
                            cout << "Invalid Choice!" << endl;
                            break;
                    }
                } while (userChoice != 2);
                break;
            }
            case 2: {
                string username, password;
                cout << "Enter Username: ";
                cin >> username;
                cout << "Enter Password: ";
                cin >> password;
                if (username == "admin" && password == "password") {
                    int adminChoice;
                    do {
                        printAdminMenu();
                        cin >> adminChoice;
                        switch (adminChoice) {
                            case 1:
                                addCarInfo();
                                break;
                            case 2:
                                modifyCarInfo();
                                break;
                            case 3:
                                deleteCarInfo();
                                break;
                            case 4:
                                break;
                            default:
                                cout << "Invalid Choice!" << endl;
                                break;
                        }
                    } while (adminChoice != 4);
                } else {
                    cout << "Invalid Username or Password!" << endl;
                }
                break;
            }
            case 3:
                cout << "Goodbye!" << endl;
                break;
            default:
                cout << "Invalid Choice!" << endl;
                break;
        }
    } while (choice != 3);
    return 0;
}

在上述代码中，我们定义了一个 `Car` 结构体，用于存储汽车信息，然后定义了一个 `vector` 容器 `cars` 用于存储多个汽车信息。接下来，我们定义了一些函数用于打印菜单界面和执行用户选择的操作，例如查看汽车信息、添加汽车信息、修改汽车信息、删除汽车信息等。

在 `main` 函数中，我们使用一个 `do-while` 循环来实现用户不断选择菜单选项的功能。当用户选择普通用户或管理员用户时，我们再使用一个嵌套的 `do-while` 循环来实现用户不断选择用户菜单或管理员菜单选项的功能。当用户选择退出时，我们退出循环并结束程序。

当然，上述代码只是一个基本的示例，实际应用中可能还需要加入更多的功能和处理更多的异常情况。