#Can I reference subclasses as a pointer to a superclass in another class?

22 messages · Page 1 of 1 (latest)

spice oak
# 
class foo
{
public:
  int x;
  int y;
};
class bar : public foo
{
public:
  std::string str;
};
class moo : public foo
{
public:
  bar *left; // Can be either foo or bar.
  bar *right;
  char c;  
};```
Can I do that? Else, what am I supposed to do?
spare pecanBOT
#

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deft canopy
# 
bar *left; // Can be either foo or bar.

this comment is false, it can only be a bar*

#

if it can either be a foo or bar object have a base class pointer

spice oak
deft canopy
#

yeah, that would be the only way if it can be both

spice oak
#

Thanks a lot.

#

!solved

spare pecanBOT
#

Thank you and let us know if you have any more questions!

spice oak
# deft canopy yeah, that would be the only way if it can be both

Sorry to bother again, but I didn't want to polute with another post. I have this class:

class astAdd : public astNode
{
public:
    astNode *left;  // uninitialized
    astNode *right; // uninitialized
    bool isEvaluable = left->isEvaluable && right->isEvaluable;
    void print()
    {
        std::cout << '(';
        left->print();
        std::cout << '+';
        right->print();
        std::cout << ')';
    }
    long long int eval()
    {
        return left->eval() + right->eval();
    }
    astAdd(astNode *__left, astNode *__right)
    {
        left = __left;
        right = __right;
        isEvaluable = left->isEvaluable && right->isEvaluable;
    }
};```
And I'd like to know how I'm supposed to initialize them. I've tried with `astNode()`, but that obviously didn't work as I intended (initializing with default values).
#

Initialize the first two astNode*, that is.

deft canopy
# 
__left

this is not a legal name btw

spice oak
deft canopy
#

well it's more 2 underscores is reserved

spice oak
#

Using only 1 would be bad practice?

deft canopy
#

well, depending on the context it's reserved as well

#

or atleast an underscore and a capital

#

and uderscores in global namespaces I believe

#

but yeah a few things use initializer lists instead of setting it in the constructor body

#

make eval const

#

well the reason it's complaining about unitialized values is cause they technically are till the body gets run

spice oak
#

That makes sense.