Why does my hash table have blank fields

Posted on 2004-11-10
Medium Priority
Last Modified: 2010-04-01
Good afternoon, I am sorry to bother and I am just stuck and not sure of something. I am creating a hash table with with my load factor a prime number and I am loading it into a vector. Now when I search for a value in my hash table. It is saying it isn't found because once it finds a blank field it thinks it is done. Now is my hash table supposed to have blank spots and if so how do I get pass that in my search knowing that I have not looked through the entire hash table? Thanks for the help
Question by:Corey_819
LVL 16

Accepted Solution

PaulCaswell earned 120 total points
ID: 12553400
There should be blank spots in your table but they should signify that the search has failed.

When adding items, the hash function calculates a 'first' location to look in for the item. If that location is already occupied with a different record, the next free location is taken.

When searching for items, the same hash function should generate the same location to begin searching.

I would suggest that your implementation is incorrect for adding items.

LVL 10

Expert Comment

ID: 12553402
Please post some code so thtaw we could help in a better way


Expert Comment

ID: 12572927
You said that you are using vector is this the STL vector ?
What data type are you using to hold the raws?

is it something like this?

typedef std::vector<std::string> myRaw;
std::map<unsigned long,myRaw*> myHash

// lets say you want to remove element with value 1234566767:

keyToRemove = 1234566767
myRaw *raw = myHash[keyToRemove ];//return the vector with this value

while ( /* iterate the raw*/ )
    if( *raw[i] == value_to_remove)


Author Comment

ID: 12583979
Thanks PaulCaswell I did figure it out I was not realizing but after I displayed my vector it was getting cleared out with all my data. And I didn't see it because I saw it being displayed when I was running my program. Thanks for the help though. :)

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