vector of vector

Question

for example we have following code pragment

#include <iostream>
#include <ostream>
#include <vector>
using namespace std;

int main() {
    vector<vector<int>>v;
    return 0;  
}

i have question as i see this form v.push_back(11) does not work what will be correct?

Answer 1

vector<vector<int>>v;

needs to be

vector<vector<int> >v;

The consecutive >> acts as the actual >> operator.

Answer 2

#include <iostream>
#include <ostream>
#include <vector>
using namespace std;

int main() {
    vector<vector<int> >v;
    vector<int> a;
    a.push_back(11);
    v.push_back(a);
    return 0;  
}

I think this should work right :)