Question

我正在尝试编写数学集合类。我的想法是制作一个称为Set的基类。然后我写了Set类的两个子类。即FiniteSet类和CountableSet类（可以处理无限集合）。我的问题是，那些子类彼此依赖，而我无法解决这个问题。我也将欣赏完全不同的解决方案。

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Answer 1

在定义类之前声明它们，例如：

//--------------------------------------------------------
//Set class
//--------------------------------------------------------
class Set
{
public:
    //some virtual functions

protected:
    //some attributes 
};

//--------------------------------------------------------
// Declare FiniteSet class
//--------------------------------------------------------
class FiniteSet : public Set
{
public:
    //implements all virtual functions 

    //function which needs to know CountableSet:
    Set unionWith(Set* otherSet);

private:
    //some attributes
};

//--------------------------------------------------------
// Declare CountableSet class
//--------------------------------------------------------
class CountableSet : public Set
{
public:
    //implements all virtual functions 

    //function which needs to know FiniteSets
    Set intersectWith(Set* otherSet);

private:
    //some attributes
};

// Define FiniteSet::unionWith
Set FiniteSet::unionWith(Set* otherSet);
{
    if(typeid(CountableSet) != typeid(*otherSet))
    {
        //the other set is finite. We can simply add all             
                    //elements from otherSet to this set.
    }
    else
    {
        //create a CountableSet and return it
    }
}

// Define CountableSet::intersectWith
Set CountableSet::intersectWith(Set* otherSet)
{
    if(typeid(FiniteSet) == typeid(*otherSet))
    {
        //do something and return FiniteSet
    }
    else
    {
        //do something and return occasionally CountableSet
    }
}

如何编写子类相互依赖的基类？

1 个答案: