// Source code example for "A Practical Introduction
// to Data Structures and Algorithm Analysis"
// by Clifford A. Shaffer, Prentice Hall, 1998.
// Copyright 1998 by Clifford A. Shaffer

// Hashtable driver class.  Use some really simple hash
// and probe functions for testing purposes.
public class HashTable {
  private int M;
  private Elem[] T;

  private int h(int key) {
    return key % M;
  }

  private int p(int key, int slot) {
    return slot;
  } 

  HashTable(int m) {
    M = m;
    T = new Elem[M];
  }
void hashInsert(Elem R) {             // Insert record R into T
  int home;                           // Home position for R
  int pos = home = h(R.key());        // Initial position
  for (int i=1; T[pos] != null; i++) {
    pos = (home + p(R.key(), i)) % M; // Next pobe slot
    Assert.notFalse(T[pos].key() != R.key(),
                    "Duplicates not allowed");
  }
  T[pos] = R;                         // Insert R
}
Elem hashSearch(int K) { // Search for the record with key K
  int home;              // Home position for K
  int pos = home = h(K); // Initial position
  for (int i = 1; (T[pos] != null) && (T[pos].key() != K); i++)
    pos = (home + p(K, i)) % M;    // Next probe position
  if (T[pos] == null) return null; // K not in hash table
  else return T[pos];              // Found it
}

}