I have a shapefile of India with states (probably as polygons). I want to convert each polygon into equally divided cells ("raster" way), and populate (actually coloring) each cell by a value that would be calculated from an algorithm which is cell's location specific. This should be done for all the cells in the polygon (programmaticall...
Suppose I have a std::vector (let's call it myVec) of size N. What's the simplest way to construct a new vector consisting of a copy of elements X through Y, where 0 <= X <= Y <= N-1? For example, myVec [100000] through myVec [100999] in a vector of size 150000. If this cannot be done efficiently with a vector, is there another STL da...
I'm trying to return an iterator for a vector in a templated class (I'm not sure if that makes a difference, but I've read that may, so I thought I'd mention it). The problem is that I get an error about C++ not supporting default-int when I try this. I've looked online and from what I can see in forums and explanaions, I don't think I...
I've run into a really strange bug, that I'm hoping someone can explain. I have a simple std::vector<V3x>, where V3x is a 3d vector (the linear algebra kind.) The following code causes a std::length_error exception to be thrown: std::vector<V3x> vertices; int vertexCount = computeVertexCount(); vertices.resize(vertexCount); // throws st...
I know that R works most efficiently with vectors and looping should be avoided. I am having a hard time teaching myself to actually write code this way. I would like some ideas on how to 'vectorize' my code. Here's an example of creating 10 years of sample data for 10,000 non unique combinations of state, plan1 and plan2: st<-NULL p1<-...
So earlier I answered my own question on thinking in vectors in R. But now I have another problem which I can't 'vectorize.' I know vectors are faster and loops slower, but I can't figure out how to do this in a vector method: I have a data frame (which for sentimental reasons I like to call my.data) which I want to do a full marginal a...
One meme that gets stressed with Java development is always use ArrayList over Vector. Vector is deprecated. That may be true, but Vector and Hashtable have the advantage that they are synchronized. I am working with a heavily concurrent oriented application, wouldn't it benefit to use objects that are synchronized like Vector? It se...
Hi, I've this sample program of a step that I want to implement on my application. I want to push_back the int elements on the string separately, into a vector. How can I? #include <iostream> #include <sstream> #include <vector> using namespace std; int main(){ string line = "1 2 3 4 5"; //includes spaces stringstream lineS...
When using the std::for_each, class A; vector<A*> VectorOfAPointers; std::for_each(VectorOfAPointers.begin(), VectorOfAPointers.end(), std::mem_fun(&A::foo)); If we have classes inheriting from A and implementing foo(), and we hold a vector of pointers to A, is there any way to call a polymorphic call on foo(), rather then explicitl...
Looking at some code I'm maintaining in System Verilog I see some signals that are defined like this: node [range_hi:range_lo]x; and others that are defined like this: node y[range_hi:range_lo]; I understand that x is defined as packed, while y is defined as unpacked. However, I have no idea what that means. What is the differenc...
Hi, I want to create a really easy to use 2D Grid. Each cell in the grid needs to be able to store a load of data. Ideally I would like to be able to traverse through the grid one cell at a time, as well as obtain the immediate neighbours of any of the grid cells. My first thought was to store a vector of pointers to a Cell's neighbour...
So, it's been a few months since I wrote this question, since then I've toyed with "raw" C++ D3D, The Ogre and Irrlicht graphics engines and lately Microsoft XNA. I've built a few 2D games (mostly replicas of old stuff like tetris, astreoids, etc.) and made some (very) small steps into the 3D world in the above mentioned technologies. I...
I'm trying to create a generic function that removes duplicates from an std::vector. Since I don't want to create a function for each vector type, I want to make this a template function that can accept vectors of any type. Here is what I have: //foo.h Class Foo { template<typename T> static void RemoveVectorDuplicates(std::vector<T...
From what i know a vector is guaranteed to be continuous and i can write a chunk of memory to it and do send of fwrite with it. All i need to do is make sure i call .resize() to force it to be the min length i need then i can use it as a normal char array? would this code be correct v.resize(numOfElements); v.clear(); //so i wont get nu...
I have a list of files (stored as c style strings) that I will be performing a search on and I will remove those files that do not match my parameters. What is the best container to use for this purpose? I'm thinking Set as of now. Note the list of files will never be larger than when it is initialized. I'll only be deleting from the con...
I want to use Vectors in a C# application I'm writing, sepcifically a Vector3. What's the best way for me to get a Vector type without writing my own? ...
So I'm reading the "3D Math Primer For Graphics And Game Development" book, coming from pretty much a non-math background I'm finally starting to grasp vector/matrix math - which is a relief. But, yes there's always a but, I'm having trouble understand the translation of an object from one coordinate space to another. In the book the a...
Ok, so - this is heavily related to my previous question Transforming an object between two coordinate spaces, but a lot more direct and it should have an obvious answer. An objects local coordinate space, how do I "get a hold of it"? Say that I load an Orc into my game, how do I know programatically where it's head, left arm, right arm...
I have 2 vector of with one has vec1{e1,e2,e3,e4} and the other one with vec2 {e2,e4,e5,e7} How to effectively get three vector from above vectors such that 1.has elements that is available only in vec1 similarly 2 has only vec2 elements and 3.with common elements ...
For instance. I have some structure: s_Some{ std::string lable; s_some_junk some_junk; }; And a vector: std::vector<s_Some> mSome; And then I fill this vector with a lot of s_Somes. I need to find an iterator for a single s_Some in this vector, which has a specific lable. So far I just iterate through all of this junk and mat...