C++ class with const pointer as data member, destructor and no default constructor

Question

I came across this C++ code. What are the issues in it? I can see that copy and assignment will be an issue, because a pointer is used as data member.

class Vehicle
{
    char const* type;
public:
    Vehicle(char const* tt) : type(tt) {}
    char const* getType() const
    {
        return type;
    }
    ~Vehicle()
    {
        delete type;
    }
};

Possible duplicate of [What is The Rule of Three?](https://stackoverflow.com/questions/4172722/what-is-the-rule-of-three) — Richard Critten, Jun 09 '18 at 08:56
Whoever even came up with this is in dire need of a good C++ book. And the last sentence of yours suggests you are, too. — Baum mit Augen, Jun 09 '18 at 08:57
`delete type;` I mistrust this. The class isn't self-contained, aka it isn't well designed and should be eradicated. — DeiDei, Jun 09 '18 at 08:57

score 2 · Answer 1 · answered Jun 09 '18 at 09:20

A trivial bit of refactoring makes this class much more stable, at the expense of a string copy:

class Vehicle
{
    std::string type;
public:
    Vehicle(char const* tt) : type(tt) {}
    char const* getType() const
    {
        return type.c_str();
    }
};

Then I'd suggest that you change the return type of getType() to a const std::string&:

const std::string& getType() const
{
    return type;
}

At least then you don't need to worry about the returned pointer of a getType type being invalidated if the type member is changed.

C++ class with const pointer as data member, destructor and no default constructor

1 Answers1