Unvalid use of non-static data member

Question

Hello am having some problems understanding what it is the compiler complains about for this snippet of code.

template<typename T> struct sEventColl {
T __d__;
list<string>  event_list;


sEventColl(T d, const string& eventStr) :
        __d__(d) {
    event_list.push_back(eventStr);
}

template<typename U>
sEventColl(const sEventColl<U>& other) {
    __d__ = other.__d__;

     this->event_list.clear();

    for (typename list<string>::const_iterator it =
            other.event_list.crbegin(); it != other.event_list.crend();
            it++) {
        event_list.push_back(*it);
    }
}

 ~sEventColl(){}

bool operator<=(const T & d) const {
    return ((d == __d__) || (__d__ < d));
}

bool operator>=(const T & d) const {
    return ((__d__ == d) || (__d__ > (d)));
}

bool removeEvent(string eventText) {

    for (typename list<string>::iterator it = event_list.begin();
            it != event_list.end(); it++) {
        if (*it == eventText) {
            event_list.erase(it);
            return true;
        }
    }
    return false;
}

bool addEvent(const string event) {

    /* Check if object already exist */
    for (typename list<string>::const_iterator it = event_list.begin();
            it != event_list.end(); it++) {
        if (event == *it)
            return false;
    }
    event_list.push_back(event);
    return true;
}

bool isEmpty() {
    return event_list.empty();
}

friend ostream& operator<<(ostream & os, const sEventColl & ecoll) {
    for (typename list<string>::const_iterator it = ecoll.cbegin();
            it != event_list.cend(); it++) {
        os << __d__ << " : " << *it << endl;
    }
    return os;
}

};

Output from compiler:

calendar.h: In function 'std::ostream& lab2::operator<<(std::ostream&, const lab2::sEventColl&)': calendar.h:49:16: error: invalid use of non-static data member 'lab2::sEventColl::event_list' calendar.h:110:11: error: from this location calendar.h:48:4: error: invalid use of non-static data member 'lab2::sEventColl::d' calendar.h:111:10: error: from this location

Looks like the same issue as this question: https://stackoverflow.com/questions/16002417/invalid-use-of-non-static-data-member-when-accessing-a-templated-class-field?rq=1 — Chris Hayes, Jan 05 '14 at 05:26
Im such an idiot, just realized i was actually making a static access to the data member on the operator<< method..that solved my problems — me_L_coding, Jan 05 '14 at 05:28
`__d__` is a [reserved name.](http://stackoverflow.com/questions/228783/what-are-the-rules-about-using-an-underscore-in-a-c-identifier) — James McNellis, Jan 05 '14 at 05:32

score 0 · Answer 1 · answered Jan 05 '14 at 05:30

Solved it..

In the

friend ostream& operator<<(ostream & os, const sEventColl & ecoll) {
for (typename list<string>::const_iterator it = ecoll.cbegin();
        it != event_list.cend(); it++) {
    os << __d__ << " : " << *it << endl;
}
return os;

}

I should have accessed the members through the ecoll reference!

Unvalid use of non-static data member

1 Answers1