Visual C++ :: Hash Table - How To Setup Static Variable

Apr 22, 2014

I am having trouble getting the cout statements that I commented out to work properly. And I can't figure out why the first movie in the movies.txt file displays at the end of the list in my output screen when it should only display once as the first item. I am also having trouble figuring out where and how to set up the static variable.

Purpose : This assignment requires that you to develop a program using the classes listed above. Specifically you will build a hash table containing movie data. The collision strategy will be to build linked lists as the array elements.

Program Specifications : Your program will read the data from the file named Movies.txt located in the StudentFiles1.zip file on the Connections Portal. Each record contains 2 fields separated by a space. They are:

FieldsData Type
Motion Picture Association Code (MPAC)Integer
Movie NameString

Your application program will read each record, create a Movie structure instance and place that structure instance into the hash table.

You will need to modify the appropriate code to provide for an audit trail of the hash table construction. To accomplish this, you will use cout statements in the above class member functions. You will need to modify them to include couts, but the modifications will be relatively small. If not, you are doing it wrong. The hashing algorithm to use is:

Index = int ( 0.618033 * MPAC) % size

Make the array size a constant and set it to 10.

Include a counter for the number of collisions that occurred in building the hash table. Including a static variable in the LinkedList or List class is the best method for doing that.

See the sample audit trail below for the first 5 records on Movies.txt and the size of the hash table set to 3. This is shown for illustration only. The full file will have different locations calculated.

1101-Casablanca is being added
The hashed location is 2
There was no collision loading 1101-Casablanca
------------------------------------------------
1200-Duck Soup is being added
The hashed location is 0
There was no collision loading 1200-Duck Soup
------------------------------------------------

[Code] ....

After the above is displayed, prompt the user to enter the MPAC of a movie to locate. Produce an audit trail when locating the requested movie as shown below: Make sure you list all movies that have collided at the hashed location. That may also cause you to modify one of the existing ADTs a little.

Will search for 6601
at the hashed location is 2
There was a collision here with 6601-Wizard of Oz
There was a collision here with 1101-Casablanca
retrieved from hash table: 6601-Wizard of Oz

[Code] ....

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C++ :: Hash Table Program - Sorting Pointer Table After All Of Values Entered

Nov 19, 2013

I am having an issue with my sort function. This is one part of the Hash table program. The main issue is that I am trying to sort the pointer table after all of the values have been entered. The ptr_sort function is not a class function and so I am therefore unable to use the class variables psize and pTable. Is there another way I should be trying this? it is a Vector should I use the sort() function from the vector class in STL?

#include "/home/onyuksel/courses/340/progs/13f/p9/util9.h"
#include "/home/onyuksel/courses/340/progs/13f/p9/hTable.h"

#ifndef H_TABLE1
#define H_TABLE1
void ptr_sort ( );

[Code] ....

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Apr 18, 2013

I have a problem with this function that adds a new value to the hash table or updates its data if the value already exists:

Code:

int tab_add(tab_disp *td, const object *value) the function should return:
TABDISP_OK if the value is correctly added, or TABDISP_ERROR if memory error, or TABDISP_INVALID if pointer td = NULL

The type of structure I am using is the following:

Code:

typedef struct {
char key[25];
char value[100];
} object;

[code]....

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Aug 5, 2013

Here is the code,

Code:
class A {
};
A& CreateObject() {
static A a;
return a;
} static A aa;
int main() {
return 0;
}

So is there any difference between a defined in CreateObject and aa?

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Code: I have these two columns.

ID Group
0 2
1 2
2 3
3 4
4 4
5 4
6 4
7 4 Code: I want to store ID values on the bases of same Group, like we do in Hash table (key, value) .

Group ID
2 0,1
3 2
4 3,4,5,6,7

so when i said key 2 it will give me 0,1. how can i do it. As first i thought that i can use array of array but then how i can store the value of key. Now I am thinking of hash but i don't know how I will store and retrieve these values.

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I am having problems with this function:

bool HashTable::insert(char const * const key, const Player& aPlayer) {
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size_t index = calculateIndex(key);
for(int i=0; i < capacity; i++) {

[Code] ....

The inserting part works just fine, but the checking for duplicates where I compare the two values is crashing my program.

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Feb 25, 2013

I'm trying to retrieve the Player object from my hash table so I can edit the content of that object. Here is what I have.

Player* HashTable::retrieve(char * key, Player& aPlayer) {
//calculate the retrieval position (the index of the array)
size_t index = calculateIndex(key);
//search for the data in the chain (linked list)
node * curr = table[index];
char id[100];

[Code] .....

Here I'm calling the retrieve and I need to return a pointer of that object.

Player* PlayerDB::FetchPlayer(char* name) {
Player* info = new Player();
out << "Fetching player " << """ << name << "" -- ";
if(h.retrieve(name, *info)) {
out << "Success!" << endl;

[Code] .....

And here is my call in main.
Player* outPlayer = NULL;
outPlayer = pdb.FetchPlayer("Sappho");
if (outPlayer != NULL) {
outPlayer->LevelUp();
}

I'm just trying to change the actual level of the player using the LevelUp function, but right now it is not making that change. I've been told I need to return a reference of the object in my retrieve function, but I thought that was what I was doing already.

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I am getting a strange runtime error when trying to run my hash table program. I have it separated in 3 separate files. I believe I have narrowed down where the error is occurring. It is either happening in insert(const &string s) or in the implementation of vector<list<string>> ht. I would appreciate some input. This is the implementation of insert():

void HTable::insert(const string &s) {
int h = hash(s);
cout<<h<<endl;
list<string> &tempList = ht[h];

[Code] .....

And it is giving me some sort of compilation error saying I cannot convert a type string to type list.

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I am working on creating a program using HashTables. This is for homework. This is the first time I am using and creating HashTables, so forgive me in advance as to I don't know entirely what I am doing. The main problem I am having right now is incorporating my remove() function. I can get the code to compile, but when I run test the program out, it crashes. The error that I am receiving is list iterator is not decrementable Here is my hashtable class as well as my remove() function. Also need to incorporate a print method.

class HTable
{
public:
HTable(int size);

[Code]....

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my insert() function

template <class T>
class Node
{
public:

[Code]....

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Here is my code so far:

Code:
//LINEAR CHAINING OR SEPERATE CHAINING...
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <ctype.h>

#define MAX_USERNAME_LEN 15
#define MAX_PASSWORD_LEN 20

[Code] ....

When I compile I get this error:

Code:
simpleauth.c: In function ‘initialize_table’:
simpleauth.c:179:30: error: incompatible types when assigning to type ‘DBEntry’ from type ‘void *’

I am sure its a simple error but I cannot seem to figure out how to set all the entries in the database to NULL. My plan is this:

1. Set all entries to NULL.
2. Check if entry is empty, if empty insert into hash-location, if not increment until empty...

Part 2 seems easy to me, but I cannot set them to empty....

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I have a large hash table, where each index has a container that has a doubly linked list. Things work up until releasing the memory. Each record is created with malloc, and each record->data is also created with malloc and the associated string is copied in using strcpy(). The table itself is released in another part of the program and doesn't produce and error.

/**
* valgrind --track-origins=yes
*/
==16898== Conditional jump or move depends on uninitialised value(s)
==16898== at 0x8049685: shFree (SpellHash.c:110)
==16898== by 0x8049352: unload (dictionary.c:115)
==16898== by 0x8048E64: main (speller.c:158)
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[Code] .....

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template<class T>
class hashTable{
public:
hashTable(int size);
~hashTable();

[Code] .....

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The next typedef was given to me like so:

typedef typename HashTable::value_type valueType;

This is giving me a world of unintelligible error messages. This is how it starts.

In instantiation of 'struct std::__detail::__is_noexcept_hash<int, sparseMatrix<int>::TupleHash>':|
recursively required from 'struct std::__and_<std::is_default_constructible<sparseMatrix<int>::TupleHash>, std::is_copy_assignable<sparseMatrix<int>::TupleHash>, std::__detail::__is_noexcept_hash<int, sparseMatrix<int>::TupleHash> >'|

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template <typename T, typename X>
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HashNode<T,X> NodeTemp;
list<HashNode<T,X>> temp;
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[Code] ....

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