Ninth Commit

Author: Chavez0296

Hashtable/HashChainApp.java

@@ -0,0 +1,216 @@
+package Hashtable;
+import java.io.*;
+
+class Link
+{
+    private int iData;// data item
+    public Link next; // next link in list
+//----------------------------------------------------------------------------------//
+    public Link(int ii)
+    {
+        iData = ii;
+    }
+//----------------------------------------------------------------------------------//
+    public int getKey()
+    {
+        return iData;
+    }
+//----------------------------------------------------------------------------------//
+    public void displayLink()
+    {
+        System.out.print(iData + " ");
+    }
+}
+class SortedList
+{
+    private Link first;
+//----------------------------------------------------------------------------------//
+    public SortedList()
+    {
+        first = null;
+    }
+//----------------------------------------------------------------------------------//
+    public void insert(Link theLink)
+    {
+        int key = theLink.getKey();
+        Link previous = null;
+        Link current = first;                               //start at first
+
+        while( current != null && key > current.getKey() )  // until the end of the list or current > key
+        {
+            previous = current;                             
+            current = current.next;                         // go to next item
+        }
+        if(previous == null )                               //if beginning of list, first --> newLink
+            first = theLink;
+        else                                                // not at beginning, 
+            previous.next = theLink;                        // prev --> newLink
+        theLink.next = current;                             // newLink --> current
+    }
+//----------------------------------------------------------------------------------//
+    public void delete(int key)
+    {
+        Link previous = null;
+        Link current = first;
+
+        while( current != null && key != current.getKey() )
+        {
+            previous = current;
+            current = current.next;
+        }
+
+        if(previous == null)
+            first = first.next;
+        else    
+            previous.next = current.next;
+    }
+//----------------------------------------------------------------------------------//
+    public Link find(int key)
+    {
+        Link current = first;
+
+        while (current != null && current.getKey() <= key) {
+            if(current.getKey() == key)
+                return current;
+            current = current.next;
+        }
+        return null;
+    }
+//----------------------------------------------------------------------------------//
+    public void displayList()
+    {
+        System.out.print("List (first-->last): ");
+        Link current = first;
+        while(current != null)
+        {
+            current.displayLink();
+            current = current.next;
+        }
+        System.out.println("");
+    }
+}
+class HashTable
+{
+    private SortedList[] hashArray;
+    private int arraySize;
+//----------------------------------------------------------------------------------//
+    public HashTable(int size)
+    {
+        arraySize = size;
+        hashArray = new SortedList[arraySize];
+        for(int i = 0; i < arraySize; i++)
+            hashArray[i] = new SortedList();
+    }
+//----------------------------------------------------------------------------------//
+    public void displayTable()
+    {
+        for(int i = 0; i < arraySize; i++)
+        {
+            System.out.print(i + ", ");
+            hashArray[i].displayList();
+        }
+    }
+//----------------------------------------------------------------------------------// 
+    public int hashFunc(int key)
+    {
+        return key % arraySize;
+    }
+//----------------------------------------------------------------------------------// 
+    public void insert(Link theLink)
+    {
+        int key = theLink.getKey();
+        int hashVal = hashFunc(key); //hash the key
+        hashArray[hashVal].insert(theLink); //insert at hashVal
+    }
+//----------------------------------------------------------------------------------// 
+    public void delete(int key)
+    {
+        int hashVal = hashFunc(key); //hash the key
+        hashArray[hashVal].delete(key); // delete link
+    }
+//----------------------------------------------------------------------------------// 
+    public Link find(int key)
+    {
+        int hashVal = hashFunc(key);                //hash the key
+        Link theLink = hashArray[hashVal].find(key); //get link
+        return theLink;
+    }
+//----------------------------------------------------------------------------------// 
+}
+class HashChainApp {
+    public static void main(String[] args) throws IOException
+    {
+        int aKey;
+        Link aDataItem;
+        int size, n, keysPerCell = 100;
+
+        System.out.print("Enter size of the hash table: ");
+        size = getInt();
+        System.out.print("Enter initial number of items: ");
+        n = getInt();
+
+        HashTable theHashTable = new HashTable(size);
+
+        for(int i = 0; i < n; i++)
+        {
+            aKey = (int)(java.lang.Math.random() * keysPerCell * size);
+            aDataItem = new Link(aKey);
+            theHashTable.insert(aDataItem);
+        }
+
+        while(true)
+        {
+            System.out.print("Emter first leter of ");
+            System.out.print("show, insert, delete, or find: ");
+            char choice = getChar();
+            switch(choice)
+            {
+                case 's':
+                    theHashTable.displayTable();
+                    break;
+                case 'i':
+                    System.out.print("Enter key value to insert: ");
+                    aKey = getInt();
+                    aDataItem = new Link(aKey);
+                    theHashTable.insert(aDataItem);
+                    break;
+                case 'd':
+                    System.out.print("Enter key value to delete: ");
+                    aKey = getInt();
+                    theHashTable.delete(aKey);
+                    break;
+                case 'f':
+                    System.out.print("Enter key value to find: ");
+                    aKey = getInt();
+                    aDataItem = theHashTable.find(aKey);
+                    if(aDataItem != null)
+                        System.out.print("Found " + aKey);
+                    else
+                        System.out.println("Could not find " + aKey);
+                    break;
+                default:
+                    System.out.print("Invalid Entry\n");
+            }
+        }
+    }
+//----------------------------------------------------------------------------------//
+    public static String getString() throws IOException 
+    {
+        InputStreamReader isr = new InputStreamReader(System.in);
+        BufferedReader br = new BufferedReader(isr);
+        String s = br.readLine();
+        return s;
+    }
+//----------------------------------------------------------------------------------//   
+    public static char getChar()throws IOException
+    {
+        String s = getString();
+        return s.charAt(0);
+    }
+//----------------------------------------------------------------------------------//
+    public static int getInt() throws IOException
+    {
+        String s = getString();
+        return Integer.parseInt(s);
+    }
+}