public HashNode Get(string key)
{
int hash = HashFunction(key);
int index = hash % TABLE_SIZE;
HashNode node = _HashTable[index];
if (node != null)
{
// iterate through nodes at index, assuming any potential collisions
while (node.next != null)
{
// check for key
if (node.key == key)
{
break;
}
node = node.next;
}
if (node.key == key)
{
return(node);
}
}
return(null);
}
public void Add(string key, Object value)
{
int hash = HashFunction(key);
int index = hash % TABLE_SIZE;
if (_HashTable[index] == null)
{
// no collision
_HashTable[index] = new HashNode(key, value);
}
else
{
// collision detected
HashNode node = _HashTable[index];
while (node.next != null)
{
node = node.next;
}
node.next = new HashNode(key, value);
}
}
static void Main(string[] args)
{
// Initialization
Person[] people = new Person[]
{
new Person("George", "Washington"),
new Person("Thomas", "Jefferson"),
new Person("Abraham", "Lincoln"),
new Person("James", "Madison"),
new Person("Andrew", "Jackson"),
new Person("Alexander", "Hamilton"),
new Person("Barack", "Obama"),
new Person("George", "Bush"),
new Person("Donald", "Trump")
};
HashTable table = new HashTable();
// Insertion
System.Console.WriteLine("Do Hashtable Insertions");
System.Console.WriteLine("-----------------------");
foreach (Person p in people)
{
table.Add(p.Key, p);
}
System.Console.WriteLine("Wrote nodes to HashTable");
System.Console.Write(System.Environment.NewLine);
// Lookup
System.Console.WriteLine("Perform Lookup");
System.Console.WriteLine("--------------");
HashNode lookup1 = table.Get(new Person("Barack", "Obama").Key);
if (lookup1 != null)
{
Person result = (Person)lookup1.value;
System.Console.WriteLine("Found matching node! " + result.FirstName + " " + result.LastName);
}
else
{
System.Console.WriteLine("Did not find a matching node.");
}
HashNode lookup2 = table.Get(new Person("George", "Trump").Key);
if (lookup2 != null)
{
Person result = (Person)lookup2.value;
System.Console.WriteLine("Found matching node! " + result.FirstName + " " + result.LastName);
}
else
{
System.Console.WriteLine("Did not find a matching node.");
}
System.Console.Write(System.Environment.NewLine);
// Iteration
System.Console.WriteLine("Print Table");
System.Console.WriteLine("-----------");
HashNode[] nodes = table.GetTable();
for (int i = 0; i < nodes.Count(); i++)
{
if (nodes[i] != null)
{
HashNode node = nodes[i];
while (node != null)
{
string message = "Index: " + i.ToString() + " Key: " + node.key;
System.Console.WriteLine(message);
node = node.next;
}
}
else
{
string message = "Index: " + i.ToString() + " No Entry";
System.Console.WriteLine(message);
}
}
System.Console.ReadLine();
}