Don't really know how to search for this.

[Solarix86]

Hi all, apologies if this is posted somewhere else, not really sure what is wrong here. Code compiles fine, 0 errors and the program runs but crashes when it reaches this statement:

if(dictionary[i].meaningList->isEmpty())

int i is set, and the struct looks like this:

    
private:
        struct
        {
            string word;
            List* meaningList;
        }dictionary[MAX_TABLESZ];

Not really sure whats going on here, any help would be appreciated.

[Solarix86]

I think what im trying to ask here is how do I call the list member function isEmpty() if its in the dictionary array?

dictionary[i].meaningList.isEmpty()

doesnt seem to work.

[kbw]

If you haven't initialised meaningList, it won't pont to a List and dereferencing it in calls like meaningList->isEmpty() should cause a runtime error/crash.

[Solarix86]

#include <iostream>
#include <string>
#include <fstream>
#include <algorithm>
#include "IndDicT.h"

using namespace std;

IndDicT::IndDicT()
{
    for(int a=0; a >= MAX_TABLESZ; a++)
	{
		dictionary[a].word = "";
		dictionary[a].meaningList = new List;
	}
}

IndDicT::~IndDicT()
{
    for(int a=0; a >= MAX_TABLESZ; a++)
	{
		dictionary[a].word = "";	// set word equal to null
		delete dictionary[a].meaningList;	// call default destructor for list objects
	}
}

//return the hash value of a word. Using Division Remainder method.
//slightly modified so that i dont have to use a rehash algorithm
int IndDicT::hashKey(string word, int prime)
{
        int result=0;

        for(int i=0;i<word.length();i++)
        {
            //obatain the ASCII interger value of character i in the sting word.
            result = result + static_cast<int>(word[i]);
        }
        //make sure that the result is a positive numeric value first
        if(result < 0)
        {
            result += 1;
        }

        return(result % prime); //prime being the used prime number table value.
}

//using the word, searchs to make sure word is not in the table
//and table location is empty if it is then insert at location.
//If location is not empty rehash and step threw to locate new position.
//If word exists then the meaning is added to the end of existing meanings.
void IndDicT::insert(string keyWord, string keyMeaning)
{
    //primary hash of the key
    int i = hashKey(keyWord, MAX_TABLESZ);

    //check to see if first hashkey location is empty
    if(dictionary[i].word != "")
    {
        //check to see if key words are the same
        if(dictionary[i].word == keyWord)
        {
            //if they are insert meaning at list rear of key word
            cout << "New Meaning added to " << keyWord << " at position " << i << " : " << keyMeaning;
            dictionary[i].meaningList.insertAtRear(keyMeaning);
        }
        else
        {
            //collision has occured and the key must be rehased
            //home check for infinit loop.
            int home = i;
            int c = hashKey(keyWord, REH_TABLESZ);

            do
            {
                i = i+c;
                if(i >= REH_TABLESZ)
                {
                    //hash table wraparound
                    i = i - REH_TABLESZ;
                }
            }while((dictionary[i].word != "") && (home != i) && (keyWord != dictionary[i].word));

            if(dictionary[i].word == keyWord)
            {
                //if they are insert meaning at list rear of key word
                cout << "New Meaning added to " << keyWord << " at position " << i << " : " << keyMeaning;
                dictionary[i].meaningList.insertAtRear(keyMeaning);
            }
            else if(dictionary[i].word == "")
            {
                cout << "New Word added to dictionary :" << keyWord << " at position " << i << " with meaning : " << keyMeaning;
                dictionary[i].word = keyWord;
                dictionary[i].meaningList.insertAtRear(keyWord);
            }
            else if(home == i)
            {
                cout << "Key : " << keyWord << " and meaning could not be added to the dictionary, This may be because the dictionary is full";
                cout << "or all index locations may not have been traveresed. My sincere apologies." << endl << endl;
            }
            else
            {
                cout << "An Uknown error has occured and nothing was added to the dictionary." << keyWord << " : ";
                cout << keyMeaning << " : " << i << " ."<< endl << endl;
            }
        }
    }
    else
    {
        //check if there is a meaning asigned to the empty string
        if(dictionary[i].meaningList.isEmpty())
        {
            cout << endl << "An error has occured : position " << i << " in the table has key : " << dictionary[i].word;
            cout << " and meaning " ;
            dictionary[i].meaningList.printList();
        }
        else
        {
            cout << "New Word added to dictionary :" << keyWord << " at position " << i << " with meaning : " << keyMeaning;
            dictionary[i].word = keyWord;
            dictionary[i].meaningList.insertAtRear(keyMeaning);
        }
    }

}

//using the hashkey value to lookup words in the hash table.
List* IndDicT::lookUp(string word)
{
    return dictionary[1].meaningList;
}

//Print out the non-empty dictionary entries in alphabetical order to a file
void IndDicT::traverse()
{

}

//output dictionary entries to the screen.
void IndDicT::printTable()
{
        for(int i=0;i < MAX_TABLESZ;i++)
        {
            if(dictionary[i].word == "")
            {
                cout << i << " : " << " is empty. " << endl;
            }
            else
            {
                cout << i << " : " << dictionary[i].word << " : ";
                dictionary[i].meaningList->printList();
            }
        }
}

/*Alphanumeric function tests the word for non alphanumeric characters and
returns a bool is true or false*/
bool Alphanumeric(string word)
{
	for(int i=0; i < word.length(); i++)
	{
		if(word[i] <= 65 || word[i] >= 122)
		{
			return false;
		}
	}
	return true;
}

Please note this is not a finished piece of work :). I'm just trying to get the insert function to work. As I understand it

dictionary[a].meaningList = new List;

should intialize the list right?

[Solarix86]

IndDicT::IndDicT()
{
    for(int a=0; a >= MAX_TABLESZ; a++)
	{
		dictionary[a].word = "";
		dictionary[a].meaningList = new List;
	}
}

IndDicT::~IndDicT()
{
    for(int a=0; a >= MAX_TABLESZ; a++)
	{
		dictionary[a].word = "";	// set word equal to null
		delete dictionary[a].meaningList;	// call default destructor for list objects
	}
}

all that comes to mind is thw word D'OH!

for(int a=0; a >= MAX_TABLESZ; a++)

should be

for(int a=0; a < MAX_TABLESZ; a++)