check length of vector c++ code example

Example 1: vector length c++

#include <vector>

int main () {
    std::vector<int> v;
    auto size = v.size();
}

Example 2: numpy how to length of vector

>>> x = np.zeros((3, 5, 2), dtype=np.complex128)
>>> x.size
30
>>> np.prod(x.shape)
30