Overloading [] operator for a vector

Here is a snippet of code;
I want to overload the [] operator such that, when I try to do something like
vCont[i]->name
it should check the mask against Contmask and take specific action.

For example:

vCont contents are

vCont[0]->mask = 0x1;
vCont[1]->mask = 0x2;
vCont[2]->mask = 0x2;

If Contmask = 0x2, then only vCont[1] and vCont[2] have to be accessed.

So, is it possible to overload the [] operator so that it prints out an error message.

Code:

---


class Base
{
  unsigned int mask;
  string name;
};

class Cont
{
    unsigned int contmask;
    vector<Base *> vCont;
};

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I am not too clear on what you are trying to do, but if you really want to overload operator[] for std::vector, then you are out of luck: you cannot even modify std::vector in the first place.

If you want to overload operator[] for your own container class (Cont?) that is implemented with std::vector, then yes, you can overload operator[]. However, in view of the convention in std::vector, I would suggest that this error checking based on a mask be done by throwing an exception from an at() member function.

Furthermore, if by "take specific action" you mean to perform some other action than just returning a value, then operator[] and possibly at() are both inappropriate. Write a (member?) function with a more specific name instead.

[] i think cannot be overloaded, you could overload the () operator, and access elements in () style instead of [] :)

Quote:

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[] i think cannot be overloaded, you could overload the () operator, and access elements in () style instead of []

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operator[] can indeed be overloaded.

Quote:

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For example:

vCont contents are

vCont[0]->mask = 0x1;
vCont[1]->mask = 0x2;
vCont[2]->mask = 0x2;

If Contmask = 0x2, then only vCont[1] and vCont[2] have to be accessed.

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Code:

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if (vCont[n]->mask = goodMask) {
    //access vCont[n]
}
else {
    //don't
}

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What's the problem?