How to initialize a NTL vector in one time?

Question

In C, we can initialize a table with:

int array[3]={1,2,3};

How can we do such a thing with NTL vectors?

I guess I have declared the vector and already set its length.

For instance:

vec_ZZ vector;

vector.SetLength(3);

Thanks for your help.

Answer 1

Refer the manual here http://www.shoup.net/ntl/doc/vector.txt

I dont think you can initialize the way you want it because when you declare

Vec<T> v;

It creates an empty vector of size zero. If we have to initialize it then you will have assign another vector to it or set a length and add values to it.

Vec<T> v; is an object and you can assign only an object. May be you inherit Vec class and overload the = operator so that you can assign array to it.

Answer 2

As I mentioned in my earlier answer you can inherit the Vec class as shown below.

using namespace NTL;

class MyVec : public  Vec<int>
{
public:
        MyVec(std::initializer_list<int> input);
};

MyVec::MyVec(std::initializer_list<int> input)
{
        int n = input.size();
        this->SetLength(n);
        std::vector<int> v;
        v.insert(v.end(), input.begin(), input.end());

        for(int i=0; i<n; i++)
                this->put(i, v[i]);
}

int main()
{
        MyVec v = {1,2,3};

        for(int i=0; i<v.length(); i++)
                cout << v[i] << " ";

        return 0;
}

Dont forget to use the C++11 flag when compiling..

I use ubuntu env and I use the following

g++ -std=c++11 test.cpp -l ntl