Trying to generate random int from a class

I'm trying to implement a neural network in C++. I've created a class "neural", each neural has a vector of weight define like this :

std::vector <float> weight;

I would like to create in my main fonction a vector of neurals. Each neural has to have its weight vector fill randomly.

Here is how I've tried :

each neurals has a methode to fill the weight vector

    void neural::fillWeight(int numWeight)

{

srand(time(NULL));


    for (size_t i = 0; i < numWeight; i++)
    {
        std::cout << "on viens de mettre un poid dans le vecteur" << std::endl;
        this->poid.push_back(rand());
    }
}

I call it here :

std::vector <neural> vectN ; 

for (size_t i = 0; i < 5; i++)
{
    neural test = neural(i, 1, 4);
    vectN.push_back(test);
}

The problem is that every neural in the vector have the same weight vector. How can I solve this issue ? Thank you in advance for you help