Question

How can I use find_if with a std::list if the list contains structs? My first pseudo code attempt at this looks like this:

typename std::list<Event>::iterator found = 
    find_if(cal.begin(), cal.last(), predicate); 

The problem here is that the predicate is not directly visible in the list but inside event.object.return_number(). How am I suppose to refer to an int that is nested inside the struct and needs a get method to be accessed.

Answer 1

You can use a functor class (which is like a function, but allows you to have state, such as configuration):

class Predicate
{
public:
    Predicate(int x) : x(x) {}
    bool operator() (const Cal &cal) const { return cal.getter() == x; }
private:
    const int x;
};

std::find_if(cal.begin(), cal.end(), Predicate(x));