/**
 * The simplest hashtable I could come up with.  No generics.
 * The key must be an integer.  The value must be a string.  
 * It holds only 4 items.
 * 
 * @author gtowell
 * Created: Sep 2020
 * Modified: March 2021
 */
public class SimpleHT {
    private class Pair {
        // the key.  Once set it canot be changed
        public final Integer key;
        // the value
        public String value;
        //Create a key value pair.
        Pair(Integer ky, String val) {
            key = ky;
            value = val;
        }
    }

    /** the array in which the data will be stored */
    private Pair[] backingArray;
    public SimpleHT() {
        backingArray = new Pair[4];
    }
    private int h(int k) {
        return k%4;
    }
    public void put(Integer key, String value) {
        backingArray[h(key)] = new Pair(key, value);
    }

    public String get(Integer key) {
        return backingArray[h(key)].value;
    }
    
    public static void main(String[] args) {
        SimpleHT sht = new SimpleHT();
        for (int i=0; i<10; i++) {
            System.out.println("adding item with key=" + i + " value=" + String.format("%c", 'a'+i));
            sht.put(i, String.format("%c", 'a'+i));
        }
        for (int i=0; i<10; i++)
            System.out.println("getting key="+i+"  value="+sht.get(i));
    }

}