Question

我目前正在研究自动售货机计划。但是，我无法弄清楚如何询问用户输入并打印出选项和价格。这是我的代码的一部分，我的问题是：我如何要求用户在main（）中输入并从Base子类中获取选项。

提前谢谢。

class Product
{
  protected:
    string product_description;
    int itemCost = 0;

  public:
    virtual void consume(void)
    {
    }

    virtual int cost(void) { return this->itemCost; }
    virtual string description(void) { return product_description; }
    virtual Product* ReturnHighestCostItem(void)
    {
      return this;
    }
    virtual void RemoveHighestCostItem(void)
    {
      return;
    }
};

class Base : public Product
{
   public:
     Base(int option)
     {
       if (option == 1)
       {
         this->product_description = "Plain";
         this->itemCost = 100;
       }
       else if (option == 2)
       {
         this->product_description = "Spicy";
         this->itemCost = 150;
       }
       else if (option == 4)
       {
         this->product_description = "Chocolate";
         this->itemCost = 200;
       }
       else if (option == 8)
       {
         this->product_description = "Coconut";
         this->itemCost = 200;
       }
       else if (option == 16)
       {
         this->product_description = "Fruity";
         this->itemCost = 200;
       }
    }
};

int main()
{
   Product obj; 
   cout << "The Available descriptions are:" << obj.description()<< endl;
   return 0;
}

Answer 1

自动售货机的输入受限制。除非用户输入有效地址，否则它不应占用用户的钱。我使用的大多数自动售货机都带有一个指定行的字母，后跟一个指定列的数字，即左上角通常为A0。右侧的项可能是A1或A2等。自动售货机中的每个Product都需要映射到其中一个地址。用户可能会输入金钱（或信用卡？），然后输入他们的选择。您必须验证他们的选择，即他们指定的地址对特定产品有效，并且他们有足够的信用来购买该产品。为了更好地显示您的要求，您可以参考此图片。

您应该熟悉std::cin并获取用户输入。您可以将输入存储为std::string，以便于验证和查找关联的Product至vend。

#include <iostream>
#include <iomanip>
#include <string>
#include <limits>

int main()
{
    double credits;       ///< user input for credits
    std::string selection;  ///< user input for vending address

    std::cout << "Welcome to vending machine!" << std::endl;
    std::cout << "Please input credits to purchase an item ex. 1.00 or 5.00" << std::endl;
    std::cout << "Ready -> " << std::flush;

    // we need to enforce that the user entered a number here
    while(!(std::cin >> credits))
    {
        std::cout << "Invalid value!\nPlease input credits to purchase an item! ex. 5.00" << std::endl;
        std::cout << "Ready -> " << std::flush;
        std::cin.clear();
        std::cin.ignore(std::numeric_limits<std::streamsize>::max(), '\n');
    }

    // (optional) format output stream for displaying credits i.e. 1.00
    std::cout << std::fixed;
    std::cout << std::setprecision(2);

    std::cout << "Please make a selection (A-J,0-8) ex. B6 or A2" << std::endl;
    std::cout << "Ready (cr. " << credits << ") -> " << std::flush;
    // any input can be a std::string so we will need to post-process to make sure
    // it's a valid input (format is correct and the product exists to vend)
    std::cin >> selection;
    // TODO: validate the users selection!

    return 0;
}

自动售货机c ++

1 个答案: