473,695 Members | 1,933 Online
Bytes | Software Development & Data Engineering Community
+ Post

Home Posts Topics Members FAQ

Hash key for vector of 3 ints

Hi all,
I'm currently creating my hash key by stuffing the bits into an
unsigned long long.

key = static_cast<uin t64>(x) | (static_cast<ui nt64>(y) << 20) |
(static_cast<ui nt64>(z) << 40);

But this limits the range in x,y,z.

I've made a few attempts in Visual Studio including making an XOR of
the vector ints.
I don't think the XOR gives keys that are unique enough.

error C2440: 'type cast' : cannot convert from 'const vector3i' to
'size_t' c:\program files\microsoft visual studio 8\vc\include
Anyone have an example or hints?

Apr 9 '08 #1
0 1199

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

Similar topics

by: ding feng | last post by:
I am a beginner. So this question could be very stupid. Would anyone help me to solve this problem? A formatted txt file is read. Then i need to look into a vector who is a member of a class to search the matched string and return this string. For example, this vector has (string1, string2, ...stringn). When the formatted txt file is read, I get string j which could be a member of the above vector. This vector is a private member of...
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 HashFcn and EqualKey template args) or, 2. convert the two unsigned ints to char*s, concatenate them and use that as Key. For method 1, the difficulty I am having is in writing the HashFcn. HashFcn requires the following method
by: pmatos | last post by:
Hi all, I have a vector of vector of ints, I could use C approach by using int but I think C++ vector<vector<int> > would be easier to manage. So I have a function which creates and initializes the vector with the values I need (I know these values before hand). - What's the best way to initialize the vector<vector<int> >? Can I initilize it by enumerating its values? - If I do: v = new vector<vector<int> >(3) for example, is it
by: Jeff | last post by:
Hello- Ive never used a vector or vectors in C++ so I have a question for you all. I know I can dynamically create the size I need upfront, but is it possible to create them on the fly dynamically? That is, for a 2 dim array, I want to create the first element and then push_back the columns after that:
by: linq936 | last post by:
Hi, The following is a psudo code to describe my question: vector<int> ints; vector<int>::iterator itr; while (itr != ints.end()){ int j = some_function(*i); if (j>0){ ints.push_back(j); }
by: foxx | last post by:
I have 2D data structure, modelled as a vector of vectors of ints. I'd like to visit each one of the ints and call a function on them. Is there some smart way of doing this without using a double for loop,? I mean how could I go about creating a new kind of iterator that knows how to transverse all the ints in some sequence; or better still, does STL already have such a feature?
by: smp | last post by:
Does anyone know why making a vector of pointers is so much less efficient than a vector of objects? For a simple example: int num = 20; vector<int*v_int_ptr; v_int_ptr.reserve(num); for(int i = 0; i < num; i++) { int* my_int_ptr = new int;
by: Markus Dehmann | last post by:
Hi, I'd like to hash std::vector<intobjects using hash_set, but I'm not sure what hash function to use. Does anybody have a suggestion? Thank you! Markus
by: barcaroller | last post by:
In the boost::program_options tutorial, the author included the following code: cout << "Input files are: " << vm.as< vector<string() << "\n"; Basically, he is trying to print a vector of string, in one line. I could
by: marktang | last post by:
ONU (Optical Network Unit) is one of the key components for providing high-speed Internet services. Its primary function is to act as an endpoint device located at the user's premises. However, people are often confused as to whether an ONU can Work As a Router. In this blog post, weíll explore What is ONU, What Is Router, ONU & Routerís main usage, and What is the difference between ONU and Router. Letís take a closer look ! Part I. Meaning of...
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 effortlessly switch the default language on Windows 10 without reinstalling. I'll walk you through it. First, let's disable language synchronization. With a Microsoft account, language settings sync across devices. To prevent any complications,...
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, it seems that the internal comparison operator "<=>" tries to promote arguments from unsigned to signed. This is as boiled down as I can make it. Here is my compilation command: g++-12 -std=c++20 -Wnarrowing bit_field.cpp Here is the code in...
by: jinu1996 | last post by:
In today's digital age, having a compelling online presence is paramount for businesses aiming to thrive in a competitive landscape. At the heart of this digital strategy lies an intricately woven tapestry of website design and digital marketing. It's not merely about having a website; it's about crafting an immersive digital experience that captivates audiences and drives business growth. The Art of Business Website Design Your website is...
by: conductexam | last post by:
I have .net C# application in which I am extracting data from word file and save it in database particularly. To store word all data as it is I am converting the whole word file firstly in HTML and then checking html paragraph one by one. At the time of converting from word file to html my equations which are in the word document file was convert into image. Globals.ThisAddIn.Application.ActiveDocument.Select();...
by: TSSRALBI | last post by:
Hello I'm a network technician in training and I need your help. I am currently learning how to create and manage the different types of VPNs and I have a question about LAN-to-LAN VPNs. The last exercise I practiced was to create a LAN-to-LAN VPN between two Pfsense firewalls, by using IPSEC protocols. I succeeded, with both firewalls in the same network. But I'm wondering if it's possible to do the same thing, with 2 Pfsense firewalls...
by: adsilva | last post by:
A Windows Forms form does not have the event Unload, like VB6. What one acts like?
by: 6302768590 | last post by:
Hai team i want code for transfer the data from one system to another through IP address by using C# our system has to for every 5mins then we have to update the data what the data is updated we have to send another system
by: muto222 | last post by:
How can i add a mobile payment intergratation into php mysql website.

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.