Benutzer:Riemer

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Archivierte Version vom 2012-03-18T15:26:21+00:00. Aktuelle Version

public class HashTable {
	private DataItem[] hashArray;

	private int arraySize;

	// private DataItem bufItem; // for deleted items

	public HashTable(int size) {
		arraySize = size;
		hashArray = new DataItem[arraySize];
		// bufItem = new DataItem(-1); // deleted item key is -1
	}

	public void displayTable() {
		System.out.print("Hash Table: ");
		for (int i = 0; i < arraySize; i++) {
			if (hashArray[i] != null)
				System.out.print(hashArray[i].getKey() + " ");
			else
				System.out.print("# ");
		}
		System.out.println("");
	}

	public int hashFunction(int key) {
		return key % arraySize;
	}

	public void insert(DataItem item) {
		int key = item.getKey();
		int hashVal = hashFunction(key); // hash the key
		// until empty cell or -1,
		while (hashArray[hashVal] != null/* && hashArray[hashVal].getKey() != -1 */) {
			++hashVal; // go to next cell
			hashVal %= arraySize; // wraparound if necessary
		}
		hashArray[hashVal] = item; // insert item
	}

	public DataItem delete(int key) {
		int hashVal = hashFunction(key);

		while (hashArray[hashVal] != null) // until empty cell,
		{
			if (hashArray[hashVal].getKey() == key) {
//				DataItem temp = hashArray[hashVal]; // save item
				// hashArray[hashVal] = bufItem; // delete item
				return hashArray[hashVal] = null;
//				return temp;
			}
			++hashVal; // go to next cell
			hashVal %= arraySize; // wraparound if necessary
		}
		return null; // can't find item
	}

	public DataItem find(int key) // find item with key
	{
		int hashVal = hashFunction(key); // hash the key

		while (hashArray[hashVal] != null) // until empty cell,
		{
			if (hashArray[hashVal].getKey() == key)
				return hashArray[hashVal]; // found, return item
			++hashVal; // go to next cell
			hashVal %= arraySize; // wraparound if necessary
		}
		return null; // can't find item
	}
}

Benutzer:Riemer

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