#include <iostream>
#include <set>
 
using namespace std;
 
class taco
{
    static set<taco *> chain; // 自分自身のポインタを入れるstaticなコンテナ
 
private:
    // コンストラクタ
    taco()
    {
        // コンストラクタで自分自身のポインタをチェーンに追加
        chain.insert(this);
    }
 
    ~taco()
    {}
 
public:
    static taco *  createinstance()
    {
        return new taco();
    }
 
    static size_t count()
    {
        return chain.size();
    }
 
    static void release()
    {
        typedef set<taco *>::iterator iterator;
        for( iterator it = chain.begin(); it != chain.end(); )
        {
            iterator next = it;
            ++next;
 
            delete *it;
            chain.erase(it);
 
            it = next;
        }
        //c++11からはこのように書ける。
        //for( iterator it = chain.begin(); it != chain.end(); )
        //{
            //eraseは削除された位置の次の位置を指すイテレータを返す。
            //it = chain.erase(it);
        //}
    }
};
 
// 静的メンバの実体
set<taco *> taco::chain;
 
 
int main()
{
    // ポインタに紐付けしない
    taco::createinstance();
    taco::createinstance();
    taco::createinstance();
    taco::createinstance();
    taco::createinstance();
 
    cout << "there are " << taco::count() << " objects in the memory." << endl;
 
    taco::release();
 
    cout << "there are " << taco::count() << " objects in the memory." << endl;
}
 

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