get the size of a pointer to an array

Asked Apr 30 '21 at 14:12

Active Apr 30 '21 at 14:14

Viewed 29 times

I have this code:

static void convertData(const I* vec, std::string vectorName, std::string filename)
{
     for (unsigned i = 0; i < sizeof(*vec) / sizeof(vec[0]); i++)
     {
                    if ((i + 4) % 4 == 0)
                        fcpp << '\n';
                    if (i == sizeof(*vec) / sizeof(vec[0]) - 1)
                        fcpp << vec[i];
                    else
                        fcpp << vec[i] << ", ";
    }
}

and this is how I callit:

std::vector<float> v = {/*...*/};
convertData(v.data(),"myVec", "vectors");

so I expected to get the length of my vector but I got the length of the pointer which is 4.

how to do to get the length of the vector?

Thanks

edited Apr 30 '21 at 14:14

asked Apr 30 '21 at 14:12

Short Answer: You can't. – NathanOliver Apr 30 '21 at 14:14
naturally, there's a solution to this? – Apr 30 '21 at 14:15
4

Directly pass the vector like `const std::vector& vec` and use `vec.size()`. – MikeCAT Apr 30 '21 at 14:15
3

@chak There are, either pass the vector directly, you you add a size parameter to the function. – NathanOliver Apr 30 '21 at 14:15

get the size of a pointer to an array

0 Answers0