You need to change method remove to removeElement. A simple
typographical error I think.
Sagarika wrote:
> I am new in this group.So,if somehow my way of posting goes wrong
> please pardon.
>
> I made a program as MyHashTable described below.All I want to print
> all the elements in the hashtable as a string.What should I do? Can
> you help me?
>
> im****t java.io.*;
> im****t java.util.*;
> im****t java.util.Comparator;
>
> interface HashComparator{
> boolean isComparable(Object key);
> boolean isEqualTo(Object Key1,Object Key2);
> int hashValue(Object key);
> }
>
> interface HashTable {
> int size();
> boolean present(int p);
> boolean isEmpty(int e);
> Object key(int k);
> Object element(int e);
> Object findElement(Object key);
> void insert(Object key,Object element);
> Object removeElement(Object key);
> }
>
> class InvalidKeyException extends RuntimeException {
> InvalidKeyException(String message) {
> super(message);
> }
> }
>
> class HashTableFullException extends RuntimeException {
> HashTableFullException(String message) {
> super(message);
> }
> }
>
> class data {
> Object key,element;
>
> data() {
> key = null;
> element = null;
> }
>
> data(Object k,Object e){
> key = k;
> element = e;
> }
>
> public Object key(){ return key;}
> public Object element(){ return element; }
> public void setKey(Object k) { key = k; }
> public void setElement(Object e) { element = e; }
> }
>
> public class MyHashTable implements HashTable {
>
> static data PRESENT = new data();
>
> int m,n;
>
> data[] bucket;
> Object NON_EXISTENT_KEY;
>
> private static HashComparator C;
>
> public MyHashTable(HashComparator C1){
> n = 0;
> C = C1;
> m = 200;
> bucket = new data[m];
> }
>
> public MyHashTable(HashComparator C1,int i){
> n = 0;
> C = C1;
> m = i;
> bucket = new data[m];
> }
>
> void examine(Object Key){
> try {
> if(!C.isComparable(Key)) throw new
> InvalidKeyException("The key is not valid");
> }
> catch(NullPointerException n) { }
> }
>
> public boolean present(int x){ return (bucket[x] ==
> PRESENT); }
>
> public boolean isEmpty(int y){ return (bucket[y] == null); }
>
> public Object key(int k) { return bucket[k].key();}
>
> public Object element(int e) { return bucket[e].element();}
>
> public int size() { return n; }
>
> int findData(Object key) throws InvalidKeyException {
> examine(key);
> int x = C.hashValue(key) % m;
> int y = x;
> do {
> if(isEmpty(x)) return -1;
> if(present(x)) x = (x+1) % m;
> else if (C.isEqualTo(key(x),key))
> return x;
> else
> x = (x+1) % m;
> }while(x != y);
> return -1;
> }
>
> public Object findElement (Object key) throws
> InvalidKeyException {
> int x = findData(key);
> if(x < 0) return this.NON_EXISTENT_KEY;
> return element(x);
> }
>
> public void insert(Object key,Object element) throws
> InvalidKeyException {
> examine(key);
> try {
> int x = C.hashValue(key) % m;
> int y = x;
> do {
> if(isEmpty(x) || present(x)) {
> bucket[x] = new data(key,element);
> return;
> }
> x = (x+1) % m;
> }while(x != y);
> throw new HashTableFullException("Hash table is full.
> ");
> }
> catch(NullPointerException n) { }
> n++;
> }
>
> public Object remove(Object key) throws InvalidKeyException{
> int x = findData(key);
> if(x<0) return this.NON_EXISTENT_KEY;
> Object O = element(x);
> bucket[x] = PRESENT;
> n--;
> return O;
> }
>
> public static void main(String[] args) {
> MyHashTable T = new MyHashTable(C);
> try{
> T.insert(new Integer(1),new Integer(29));
> T.insert(new Integer(2),new Integer(45));
> T.insert(new Integer(3),new Integer(37));
> T.insert(new Integer(4),new Integer(99));
> T.insert(new Integer(5),new Integer(58));
> T.insert(new Integer(6),new Integer(76));
> T.remove(new Integer(2));
> System.out.println(); System.out.println();
> System.out.println("The table size is " + T.size());
> System.out.println();
> }
> catch(InvalidKeyException e) {
> System.out.println("The key is Invalid");
> System.out.println(e.getMessage());
> }
> }
> }
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