challenge explanation

Question

What is the output of this code?
#include <iostream>
#include <vector>
using namespace std;
class A {
public:
static int cnt;
A(int a){}
~A(){ ++cnt;}
};
int A::cnt = 0;
int main() {
vector<A> v(4, 1);
v.push_back(1);
cout << A::cnt << endl;
return 0;
}

from where cnt got 6 ?

Answer 1

there is no better than that but I will write it in my way to ensure that I understood

a temporary object is created and assigned to 1
then this object is assigned to more 4 object
then it will be destroyed makes cnt 1
after push back another 4 objects created and the old 4 objects destroyed makes cnt 5

another temporary object for (1) which is the new element will be created and destroyed so that cnt 6

vector is like a dynamic array allocated by malloc and any push is like realloc() call isn't it?