473,403 Members | 2,270 Online
Bytes | Software Development & Data Engineering Community
Post Job

Home Posts Topics Members FAQ

Join Bytes to post your question to a community of 473,403 software developers and data experts.

Hash Map

How can I use Haspmap in C++ and what will be benefit of hashmap over
arrays?

Apr 17 '07 #1
2 6182
Salman wrote:
How can I use Haspmap in C++ and what will be benefit of hashmap over
arrays?
A hash map is what's known as an associative container. It has some
specific properties that allow quick insertion and retrieval of any
element. In arrays elements are indexed, in hash maps elements are
"hashed".

If you can find an implementation of a hash map, use it. Usually
you include the header and define your container, just like you would
a 'vector' or 'list'.

V
--
Please remove capital 'A's when replying by e-mail
I do not respond to top-posted replies, please don't ask
Apr 18 '07 #2
On Apr 18, 2:27 am, "Victor Bazarov" <v.Abaza...@comAcast.netwrote:
Salman wrote:
How can I use Haspmap in C++ and what will be benefit of hashmap over
arrays?
A hash map is what's known as an associative container. It has some
specific properties that allow quick insertion and retrieval of any
element. In arrays elements are indexed, in hash maps elements are
"hashed".
If you can find an implementation of a hash map, use it. Usually
you include the header and define your container, just like you would
a 'vector' or 'list'.
You normally also have to provide a hashing function. This is
non-trivial, and if you don't understand the basic principles of
a hash map (as the original poster obviously doesn't), then the
probability of your writing an effective hashing function is
close to zero.

--
James Kanze (GABI Software) email:ja*********@gmail.com
Conseils en informatique orientée objet/
Beratung in objektorientierter Datenverarbeitung
9 place Sémard, 78210 St.-Cyr-l'École, France, +33 (0)1 30 23 00 34

Apr 18 '07 #3

This thread has been closed and replies have been disabled. Please start a new discussion.

Similar topics

3
by: Murali | last post by:
I have a requirement where I have to use two unsigned ints as a key in a STL hash map. A couple of ways to do this is 1. create a struct with two unsigned ints and use that as key (write my own...
2
by: Bryan Olson | last post by:
The current Python standard library provides two cryptographic hash functions: MD5 and SHA-1 . The authors of MD5 originally stated: It is conjectured that it is computationally infeasible to...
24
by: kdotsky | last post by:
Hello, I am using some very large dictionaries with keys that are long strings (urls). For a large dictionary these keys start to take up a significant amount of memory. I do not need access to...
12
by: Arash Partow | last post by:
Hi all, I've ported various hash functions to python if anyone is interested: def RSHash(key): a = 378551 b = 63689 hash = 0
21
by: Johan Tibell | last post by:
I would be grateful if someone had a minute or two to review my hash table implementation. It's not yet commented but hopefully it's short and idiomatic enough to be readable. Some of the code...
21
by: Hallvard B Furuseth | last post by:
Is the code below valid? Generally a value must be accessed through the same type it was stored as, but there is an exception for data stored through a character type. I'm not sure if that...
139
by: ravi | last post by:
Hi can anybody tell me that which ds will be best suited to implement a hash table in C/C++ thanx. in advanced
18
by: beginner | last post by:
Hi All. I'd like to do the following in more succint code: if k in b: a=b else: a={} b=a
5
by: Jeff | last post by:
Lets say we have what I would call a "hash": var HASH =new Array(); HASH='first'; HASH='second'; HASH='third'; I'd like to return that as JSON data. Is there a direct way to do that?
1
by: sixtyfootersdude | last post by:
Good Morning! I am a perl newbie and I think that I am struggling with references. I have an array of references to hashes which I am trying to print. This is what I have: for(my...
0
by: Charles Arthur | last post by:
How do i turn on java script on a villaon, callus and itel keypad mobile phone
0
by: emmanuelkatto | last post by:
Hi All, I am Emmanuel katto from Uganda. I want to ask what challenges you've faced while migrating a website to cloud. Please let me know. Thanks! Emmanuel
0
BarryA
by: BarryA | last post by:
What are the essential steps and strategies outlined in the Data Structures and Algorithms (DSA) roadmap for aspiring data scientists? How can individuals effectively utilize this roadmap to progress...
1
by: nemocccc | last post by:
hello, everyone, I want to develop a software for my android phone for daily needs, any suggestions?
1
by: Sonnysonu | last post by:
This is the data of csv file 1 2 3 1 2 3 1 2 3 1 2 3 2 3 2 3 3 the lengths should be different i have to store the data by column-wise with in the specific length. suppose the i have to...
0
by: Hystou | last post by:
There are some requirements for setting up RAID: 1. The motherboard and BIOS support RAID configuration. 2. The motherboard has 2 or more available SATA protocol SSD/HDD slots (including MSATA, M.2...
0
by: Hystou | last post by:
Most computers default to English, but sometimes we require a different language, especially when relocating. Forgot to request a specific language before your computer shipped? No problem! You can...
0
Oralloy
by: Oralloy | last post by:
Hello folks, I am unable to find appropriate documentation on the type promotion of bit-fields when using the generalised comparison operator "<=>". The problem is that using the GNU compilers,...
0
agi2029
by: agi2029 | last post by:
Let's talk about the concept of autonomous AI software engineers and no-code agents. These AIs are designed to manage the entire lifecycle of a software development project—planning, coding, testing,...

By using Bytes.com and it's services, you agree to our Privacy Policy and Terms of Use.

To disable or enable advertisements and analytics tracking please visit the manage ads & tracking page.