// This example shows why typename is needed.
// Don’t confuse typename with typedef.
//
// • What are the requirements of a set? 🦆
// • What are the requirements of a fussyset? 🦆
//
// Try making a fussyset of doubles, instead.

#include <iostream>
#include <set>

using namespace std;

// fussyset is just like a set, except that it doesn’t like ice cream.
// This is NOT inheritance--there is no is-a relationship.
// Instead, it’s a has-a relationship, with forwarding methods.

template <class T>
class fussyset : set<T> {
  public:
    typedef set<T>::iterator iterator;		// This won’t compile.  Why?

    void insert(const T &val) {
	if (val != "ice cream")
	    storage.insert(val);
    }
    iterator begin() const { return storage.begin(); }
    iterator end() const { return storage.end(); }
    size_t size() const { return storage.size(); }
};

int main() {
    fussyset<string> fs;
    fs.insert("apple");
    fs.insert("cereal");
    fs.insert("ice cream");
    fs.insert("apple");

    cout << "size is " << fs.size() << '\n';
    for (fussyset<string>::iterator it=fs.begin(); it!=fs.end(); ++it)
    	cout << *it << ' ';
    cout << '\n';

    for (auto d : fs)
    	cout << d << ' ';
    cout << '\n';
}