CODEWITHSUNDEEP
c++castingconstants
noɥʇʎԀʎzɐɹƆ
noɥʇʎԀʎzɐɹƆ

Reputation: 10647

Casting vector<int> to const vector<const int>

How can I cast vector<int> to const vector<const int>?

I've tried static_cast<const vector<const int>>(array) and using the value without a cast. Neither compiled.

Upvotes: 2

Views: 7282

Answers (2)

R Sahu
R Sahu

Reputation: 206577

You cannot cast a std::vector<int> to const std::vector<const int>.

Besides, it does not make sense to use a std::vector<const int> at all. It doesn't give you any more safety than a const std::vector<int>.

Not only that, C++ does not allow construction of std::vector<const T>. See Does C++11 allow vector<const T>? for more info.

Upvotes: 3

Alden
Alden

Reputation: 2269

You cannot change the type of the elements of the vector, but you can change the type of the vector to const std::vector<int> which will prevent making changes to the vector.

#include <vector>

int main()
{
    std::vector<int> v1;
    v.push_back(1);
    v.push_back(2);
    v.push_back(3);

    const std::vector<int>& v2 = v1;
    v2.push_back(4); // Causes an error
    v2[0] = 4; // Causes an error
    return 0;
}

Upvotes: 1

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