using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;

namespace EmployeeDict
{
    class Program
    {
        static void Main(string[] args)
        {
            // Create a dictionary of employees, keyed on their staff number.
            GenDictionary<string, Employee> staff = new GenDictionary<string, Employee>(100);

            // Add some employees.
            staff["007"] = new Employee("James Bond");
            staff["010"] = new Employee("Lee Trundle");

            // Get an employee.
            Employee emp = staff["010"];
            Console.WriteLine("In GenDictionary, Employee 010 is {0}.", emp);
            Console.ReadLine();
        }
    }

    public class Employee
    {
        private string name;

        public Employee(string name)
        {
            this.name = name;
        }

        public override string ToString()
        {
            return name;
        }
    }

    public class GenDictionary<K, V>
    {
        // Nested class, to represent one key/value entry in the dictionary.
        struct Entry
        {
            public K key;
            public V value;

            public Entry(K key, V value)
            {
                this.key = key;
                this.value = value;
            }
        };

        // The dictionary holds an array of entries. Each entry has a key and a value.
        private Entry[] entries;
        private int numEntries;
        private int maxEntries;

        public GenDictionary(int size)
        {
            entries = new Entry[size];
            numEntries = 0;
            maxEntries = size;
        }

        public bool Contains(K key)
        {
            // Loop through all entries, to find a key that matches the parameter key.
            foreach (Entry entry in entries)
            {
                if (entry.key.Equals(key))
                    return true;
            }
            return false;
        }

        public V this[K key]
        {
            get
            {
                // Loop through all entries, to find a key that matches the parameter key. Return the value for that entry.
                foreach (Entry entry in entries)
                {
                    if (entry.key.Equals(key))
                        return entry.value;
                }
                // Key not found, so return default value for the "value type".
                return default(V);
            }
            set
            {
                // Loop through all entries, to find a key that matches the parameter key. Set the value for that entry.
                for (int i = 0; i < numEntries; i++)
                {
                    Entry entry = entries[i];
                    if (entry.key.Equals(key))
                    {
                        entry.value = value;
                        return;
                    }
                }
                // Key not found, so add new entry at end of array (if not already full).
                if (numEntries < maxEntries)
                {
                    entries[numEntries++] = new Entry(key, value);
                }
            }
        }
    }
}