C++:模板类的向量 [英] C++ : Vector of template class

问题描述

我有一个名为 Cell 的模板类，如下所示:-

I have a template class named Cell as follows:-

template<class T>class Cell
{
    string header, T data;
}

现在我想要另一个名为 Row 的类.Row 将有一个名为 Cells 的向量，这样我就可以将 Cell 和 Cell 类型元素添加到该向量中.可能吗?

Now I want another class Named Row. Row will have a vector named Cells such that I can add both Cell and Cell type elements to that vector. Is it possible?

如果是这样，我该怎么做?提前致谢.

If so, how can I do that? Thanks in advance.

推荐答案

根据您提供的额外细节，前两个答案将不起作用.您需要的是一种称为细胞变体的类型，然后您可以拥有这些类型的向量.例如:-

With the extra detail you've provided, the first two answers won't work. What you require is a type known as a variant for the cell and then you can have a vector of those. For example:-

enum CellType
{
  Int,
  Float,
  // etc
};

class Cell
{
  CellType type;
  union
  {
    int i;
    float f;
    // etc
  };
};

class Vector
{
  vector <Cell> cells;
};

然而，添加新类型很痛苦，因为它需要大量代码来维护.另一种方法可以使用具有公共基类的单元格模板:-

This, however, is a pain to add new types to as it requires a lot of code to maintain. An alternative could use the cell template with a common base class:-

class ICell
{
  // list of cell methods
};

template <class T>
class Cell : public ICell
{
  T data;
  // implementation of cell methods
};

class Vector
{
  vector <ICell *> cells;
};

这可能会更好，因为您最初需要更新的代码较少以添加新的单元格类型，但您必须在单元格向量中使用指针类型.如果您按值存储单元格，vector ，那么您将由于 对象切片而丢失数据.

This might work better as you have less code initially to update to add a new cell type but you have to use a pointer type in the cells vector. If you stored the cell by value, vector <ICell>, then you will lose data due to object slicing.

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