How to properly static cast a vector in C++?

Javi picture Javi · Feb 28, 2014 · Viewed 7.6k times · Source

I have a code in which at the end of a function I need to cast from int to double all the elements of an array in order to being able to do a final push_back before exiting the function. The code I have right now is:

template <class T, size_t dims> class A {
    typedef typename std::array<int, dims> ArrayInt;
    typedef typename std::array<double, dims> ArrayDouble;
    typedef typename std::vector <ArrayDouble> VectorDouble;

/* ...*/

foo() {
   /*  ...*/

   ArrayInt myArrayInt;
   ArrayDouble myArrayDouble;
   VectorDouble myVectorDouble;

    /* Initialize myArrayInt 
    Do some other stuff */

    for (int i = 0; i < dims; ++i) 
        myArrayDouble[i] = static_cast<double>(myArrayInt[i]);

    myVectorDouble.push_back(myArrayDouble);
    }
}

It works properly, but I do not feel comfortable about the lines:

for (int i = 0; i < dims; ++i) 
    myArrayDouble[i] = static_cast<double>(myArrayInt[i]);

Is there any better way of doing this?

Thank you.

Answer

BЈовић picture BЈовић · Feb 28, 2014

You can use a function from algorithm.

With copy_n :

std::copy_n( myArrayInt.begin(), dims, myArrayDouble.begin() );

or with copy :

std::copy( myArrayInt.begin(), myArrayInt.end(), myArrayDouble.begin() );