写一个自动售货机界面的代码

非常感谢您的提问！以下是一个简单的自动售货机界面的代码示例：

#include <iostream>
using namespace std;

int main() {
    int choice;
    float money, price;
    bool valid_choice = false;

    cout << "Welcome to the vending machine!" << endl;
    cout << "Please select an item:" << endl;
    cout << "1. Coke - $1.50" << endl;
    cout << "2. Chips - $1.00" << endl;
    cout << "3. Candy - $0.75" << endl;

    do {
        cout << "Enter your choice (1-3): ";
        cin >> choice;

        switch (choice) {
            case 1:
                price = 1.5;
                valid_choice = true;
                break;
            case 2:
                price = 1.0;
                valid_choice = true;
                break;
            case 3:
                price = 0.75;
                valid_choice = true;
                break;
            default:
                cout << "Invalid choice. Please try again." << endl;
                break;
        }
    } while (!valid_choice);

    cout << "You have selected item " << choice << "." << endl;
    cout << "Please insert money: $";
    cin >> money;

    if (money >= price) {
        float change = money - price;
        cout << "Thank you for your purchase!" << endl;
        cout << "Your change is: $" << change << endl;
    } else {
        cout << "Insufficient funds. Please insert more money." << endl;
    }

    return 0;
}

这个程序会显示一个自动售货机的菜单，让用户选择一个商品。然后，它会要求用户输入足够的钱来购买所选商品。如果用户输入的钱足够，程序会输出一条感谢购买的消息，并显示找零的金额。如果用户输入的钱不够，程序会提示用户继续输入更多的钱。