Exam CPP topic 2 question 201 discussion

What happens when you attempt to compile and run the following code?
#include <vector>
#include <iostream>
#include <algorithm>

using namespace std;
template<class T>struct Out {
ostream & out;
Out(ostream & o): out(o){}
void operator()(const T & val ) {
out<<val<<" ";
}
};
struct Sequence {
int start;
Sequence(int start):start(start){}
int operator()() { return 10*(1+(start++ %3)); }
};
int main() {
vector<int> v1(10);
generate(v1.begin(), v1.end(), Sequence(1));
unique(v1.begin(),v1.end());
for_each(v1.begin(), v1.end(), Out<int>(cout) );cout<<endl; return 0;
}
Program outputs: