I have a class representing a user called Nick
and I want to use std::find_if
on it, where I want to find if the userlist vector has an object included with the same username I pass in. I did a few attempts by trying to create a new Nick
object for the username I want to test and overloading the == operator
and then trying to use find/find_if
on the object:
std::vector<Nick> userlist;
std::string username = "Nicholas";
if (std::find(userlist.begin(), userlist.end(), new Nick(username, false)) != userlist.end())) {
std::cout << "found";
}
I have overloaded the == operator
so comparing Nick == Nick2 should work, but the function returns error C2678: binary '==' : no operator found which takes a left-hand operand of type 'Nick' (or there is no acceptable conversion)
.
Here is my Nick class for reference:
class Nick {
private:
Nick() {
username = interest = email = "";
is_op = false;
};
public:
std::string username;
std::string interest;
std::string email;
bool is_op;
Nick(std::string d_username, std::string d_interest, std::string d_email, bool d_is_op) {
Nick();
username = d_username;
interest = d_interest;
email = d_email;
is_op = d_is_op;
};
Nick(std::string d_username, bool d_is_op) {
Nick();
username = d_username;
is_op = d_is_op;
};
friend bool operator== (Nick &n1, Nick &n2) {
return (n1.username == n2.username);
};
friend bool operator!= (Nick &n1, Nick &n2) {
return !(n1 == n2);
};
};
If you are using C++0X you can use a simple lambda expression
std::string username = "Nicholas";
std::find_if(userlist.begin(), userlist.end(), [username](Nick const& n){
return n.username == username;
})