vectors and template types

I need to iterate thru a vector which holds an unknown type. I am
using templates and it looks like this after details are removed.

template <class T>
class set
{
    vector<T> set_v;
    public:
    void insert(const T&);
};

template <class T>
void set<T>::insert(const T &t)
{
    vector<T>::iterator itr;                  //This line does not
compile. error:  expected `;' before "itr"
    //......
    //......
};

Pls let me know what i am doing wrong.