CODEWITHSUNDEEP
c++
purga
purga

Reputation: 453

Creating a type alias for a templated class

Instead of using

std::vector<Object> ObjectArray;

I would like it to be

MyArray<Object> ObjectArray;

with all the std::vector methods preserved. (like push_back(), reserve(), ...etc)

However, using

typedef std::vector MyArray;

won't work. Should I use template instead? How?

Upvotes: 10

Views: 4180

Answers (3)

Ryan Haining
Ryan Haining

Reputation: 36802

As of C++11 you can use a templated type alias

template <typename T>
using MyArray = std::vector<T>;

If you want to be more generic you can use a variadic template (which would allow for allocators in the case of vector without having to be specific)

template <typename... Ts>
using MyArray = std::vector<Ts...>;

Upvotes: 11

keraba
keraba

Reputation: 554

Another way:

#include <vector>

template <typename T>
struct MyArray
    :std::vector<T>
{
};

void func()
{
    MyArray<int> my;

    my.push_back(5);

    MyArray<int>::iterator i;
}

Compiles for me, but you may find that some things available in vector<> need to be "pulled up" into MyArray.

Upvotes: 5

Thomas
Thomas

Reputation: 181745

What you would really want is a templated typedef. Unfortunately those are not supported in the current version of C++, but they will be added in C++0x.

For now, here's a possible workaround:

template<class T> struct My {
    typedef std::vector<T> Array;
};

My<Object>::Array ObjectArray

Whether or not that is better than simply using std::vector directly, I'll leave to you to decide.

Upvotes: 14

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