ALGA/ALGA/Paradigmak/02_FunkcionalisParadigma.cs

using System;
using System.Collections;
using System.Collections.Generic;

namespace OE.ALGA.Paradigmak
{
    public class FeltetelesFeladatTarolo<T> : FeladatTarolo<T>, IEnumerable<T> where T : IVegrehajthato
    {
        public Func<T, bool> BejaroFeltetel
        {
            get;
            set;
        }
        public bool Igaz(T t)
        {
            return true;
        }
        public FeltetelesFeladatTarolo(int l) : base(l)
        {
            BejaroFeltetel = Igaz;
        }
        public void FeltetelesVegrehajtas(Func<T, bool> feltetel)
        {
            foreach (T t in tarolo)
            {
                if (t != null && feltetel(t))
                {
                    t.Vegrehajtas();
                }
            }
        }

        new public IEnumerator GetEnumerator()
        {
            FeltetelesFeladatTaroloBejaro<T> bejaro = new FeltetelesFeladatTaroloBejaro<T>(tarolo, n, BejaroFeltetel);
            return bejaro.GetEnumerator();
        }
        
    }
    public class FeltetelesFeladatTaroloBejaro<T> : IEnumerator<T> where T : IVegrehajthato
    {
        T[] tarolo;
        int n;
        int aktualisindex;
        public Func<T, bool> Feltetel
        {
            get;
        }
        public T Current
        {
            get { return tarolo[aktualisindex]; }
        }
        public FeltetelesFeladatTaroloBejaro(T[] tarolo, int n, Func<T, bool> feltetel)
        {
            this.tarolo = tarolo;
            this.n = n;
            aktualisindex = 0;
            Feltetel = feltetel;
        }
        object IEnumerator.Current => throw new NotImplementedException();

        public IEnumerator GetEnumerator()
        {
            foreach (T t in tarolo)
            {
                if (t != null && Feltetel(t))
                {
                    yield return t;
                }
            }
        }

        public void Dispose()
        {
            throw new NotImplementedException();
        }

        public bool MoveNext()
        {
            if (aktualisindex < n - 1)
            {
                aktualisindex++;
                if (Feltetel(tarolo[aktualisindex]))
                {
                    return true;
                }
                return MoveNext();
            }
            else
            {
                return false;
            }
        }

        public void Reset()
        {
            aktualisindex = -1;
        }
    }
}