how to get 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();