how to find the length of a vector code example

Example 1: vector length c++

#include <vector>

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

Example 2: finding the size of vector in c++

vector<int> a;
//to directly find the size of the vector;
//use  a.size(;

cout <<" " << a.size();

Example 3: numpy how to length of vector

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