Different addresses while filling a std::vector

Different addresses while filling a std::vector

Wouldn't you expect the addresses printed by the two loops to be the same?
I was, and I cannot understand why (sometimes) they are different.
#include <iostream>
#include <vector>
using namespace std;
struct S {
void print_address() {
cout << this << endl;
}
};
int main(int argc,char *argv[]) {
vector<S> v;
for (size_t i = 0; i < 10; i++) {
v.push_back( S() );
v.back().print_address();
}
cout << endl;
for (size_t i = 0; i < v.size(); i++) {
v[i].print_address();
}
return 0;
}
I tested this code with many local and on-line compilers and the output I
get looks like this (the last three figures are always the same):
0xaec010
0xaec031
0xaec012
0xaec013
0xaec034
0xaec035
0xaec036
0xaec037
0xaec018
0xaec019
0xaec010
0xaec011
0xaec012
0xaec013
0xaec014
0xaec015
0xaec016
0xaec017
0xaec018
0xaec019
I spotted this because making some initialization in the first loop I
obtained uninitialized object in the subsequent part of the program. Am I
missing something?