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  • push_back private vectors with 2 methods, one isn't working

    - by jmclem
    I have a class with a private vector of doubles. To access or modify these values, at first I used methods such as void classA::pushVector(double i) { this->vector.push_back(i); } double classA::getVector(int i) { return vector[i]; } This worked for a while until I found I would have to overload a lot of operators for what I needed, so I tried to change it to get and set the vector directly instead of the values, i.e. void classA::setVector(vector<double> vector) { this->vector = vector; } vector<double> classA::getVector() { return vector; } Now, say there is a classB, which has a private classA element, which also has get and set methods to read and write. The problem was when I tried to push back a value to the end vector in classA. void classB::setFirstValue(double first) { this->getClassA().getVector().push_back(first); } This does absolutely nothing to the vector. It remains unchanged and I can't figure out why... Any ideas?

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  • Oracle Database 12c Spatial: Vector Performance Acceleration

    - by Okcan Yasin Saygili-Oracle
    Most business information has a location component, such as customer addresses, sales territories and physical assets. Businesses can take advantage of their geographic information by incorporating location analysis and intelligence into their information systems. This allows organizations to make better decisions, respond to customers more effectively, and reduce operational costs – increasing ROI and creating competitive advantage. Oracle Database, the industry’s most advanced database,  includes native location capabilities, fully integrated in the kernel, for fast, scalable, reliable and secure spatial and massive graph applications. It is a foundation for deploying enterprise-wide spatial information systems and locationenabled business applications. Developers can extend existing Oracle-based tools and applications, since they can easily incorporate location information directly in their applications, workflows, and services. Spatial Features The geospatial data features of Oracle Spatial and Graph option support complex geographic information systems (GIS) applications, enterprise applications and location services applications. Oracle Spatial and Graph option extends the spatial query and analysis features included in every edition of Oracle Database with the Oracle Locator feature, and provides a robust foundation for applications that require advanced spatial analysis and processing in the Oracle Database. It supports all major spatial data types and models, addressing challenging business-critical requirements from various industries, including transportation, utilities, energy, public sector, defense and commercial location intelligence. Network Data Model Graph Features The Network Data Model graph explicitly stores and maintains a persistent data model withnetwork connectivity and provides network analysis capability such as shortest path, nearest neighbors, within cost and reachability. It loads partitioned networks into memory on demand, overcomingthe limitations of in-memory analysis. Partitioning massive networks into manageable sub-networkssimplifies the network analysis. RDF Semantic Graph Features RDF Semantic Graph has native support for World Wide Web Consortium standards. It has open, scalable, and secure features for storing RDF/OWL ontologies anddata; native inference with OWL 2, SKOS and user-defined rules; and querying RDF/OWL data withSPARQL 1.1, Java APIs, and SPARQLgraph patterns in SQL. Video: Oracle Spatial and Graph Overview Oracle spatial is embeded on oracle database product. So ,we can use oracle installer (OUI).The Oracle Universal Installer (OUI) is used to install Oracle Database software. OUI is a graphical user interface utility that enables you to view the Oracle software that is installed on your machine, install new Oracle Database software, and delete Oracle software that you no longer need to use. Online Help is available to guide you through the installation process. One of the installation options is to create a database. If you select database creation, OUI automatically starts Oracle Database Configuration Assistant (DBCA) to guide you through the process of creating and configuring a database. If you do not create a database during installation, you must invoke DBCA after you have installed the software to create a database. You can also use DBCA to create additional databases. For installing Oracle Database 12c you may check the Installing Oracle Database Software and Creating a Database tutorial under the Oracle Database 12c 2-Day DBA Series.You can always check if spatial is available in your database using  "select comp_id, version, status, comp_name from dba_registry where comp_id='SDO';"   One of the most notable improvements with Oracle Spatial and Graph 12c can be seen in performance increases in vector data operations. Enabling the Spatial Vector Acceleration feature (available with the Spatial option) dramatically improves the performance of commonly used vector data operations, such as sdo_distance, sdo_aggr_union, and sdo_inside. With 12c, these operations also run more efficiently in parallel than in prior versions through the use of metadata caching. For organizations that have been facing processing limitations, these enhancements enable developers to make a small set of configuration changes and quickly realize significant performance improvements. Results include improved index performance, enhanced geometry engine performance, optimized secondary filter optimizations for Spatial operators, and improved CPU and memory utilization for many advanced vector functions. Vector performance acceleration is especially beneficial when using Oracle Exadata Database Machine and other large-scale systems. Oracle Spatial and Graph vector performance acceleration builds on general improvements available to all SDO_GEOMETRY operations in these areas: Caching of index metadata, Concurrent update mechanisms, and Optimized spatial predicate selectivity and cost functions. These optimizations enable more efficient use of: CPU, Memory, and Partitioning Resulting in substantial query performance improvements.UsageTo accelerate the performance of spatial operators, it is recommended that you set the SPATIAL_VECTOR_ACCELERATION database system parameter to the value TRUE. (This parameter is authorized for use only by licensed Oracle Spatial users, and its default value is FALSE.) You can set this parameter for the whole system or for a single session. To set the value for the whole system, do either of the following:Enter the following statement from a suitably privileged account:   ALTER SYSTEM SET SPATIAL_VECTOR_ACCELERATION = TRUE;Add the following to the database initialization file (xxxinit.ora):   SPATIAL_VECTOR_ACCELERATION = TRUE;To set the value for the current session, enter the following statement from a suitably privileged account:   ALTER SESSION SET SPATIAL_VECTOR_ACCELERATION = TRUE; Checkout the complete list of new features on Oracle.com @ http://www.oracle.com/technetwork/database/options/spatialandgraph/overview/index.html Spatial and Graph Data Sheet (PDF) Spatial and Graph White Paper (PDF)

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  • Why don't more games use vector art?

    - by Parris
    It would seem to me that vector art is more efficient in terms of resources/scalability; however, in most cases I have seen artists using bitmap/rasterized art. Is this a limitation put on the artists by the game programmers/designers? As a programmer I think vector art would be more ideal, since it allows for scaling up resolution without having to recreate the art, creating really large graphics or causing graphics to become blurry. The questions: why aren't more people using SVG/AI to create 2D game art? Would it actually be preferred (and who prefers it)? Are bitmap graphics a standard or a limitation (or maybe neither)? Background: I am working on an engine, and I had some kinda cool ideas for vector based graphics; however, I don't want to piss off artists in the future. I guess this is more a question centered around pragmatism and developing games.

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  • Vector Graphics in DirectX

    - by Doug
    I'm curious as to people's thoughts on the best way to use vector graphics in a directX game instead of rasterized textures(think Super Meat Boy). I want to remain resolution independent and don't want to downscale/upscale rasterized graphics. Also the idea would be for all assets to be vector graphics(again think Super Meat Boy). I've looked at Valve's paper "Improved Alpha-Tested Magnification for Vector Textures and Special Effects" and also looked at using shaders http://http.developer.nvidia.com/GPUGems3/gpugems3_ch25.html. Wondering if anyone has done something similar or an alternate approach. Cheers

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  • Collision detection - Smooth wall sliding, no bounce effect

    - by Joey
    I'm working on a basic collision detection system that provides point - OBB collision detection. I have around 200 cubes in my environment and I check (for now) each of them in turn and see if it collides. If it does I return the colliding face's normal, save the old player position and do some trigonometry to return a new player position for my wall sliding. edit I'll define my meaning of wall sliding: If a player walks in a vertical slope and has a slight horizontal rotation to the left or the right and keeps walking forward in the wall the player should slide a little to the right/left while continually walking towards the wall till he left the wall. Thus, sliding along the wall. Everything works fine and with multiple objects as well but I still have one problem I can't seem to figure out: smooth wall sliding. In my current implementation sliding along the walls make my player bounce like a mad man (especially noticable with gravity on and moving forward). I have a velocity/direction vector, a normal vector from the collided plane and an old and new player position. First I negate the normal vector and get my new velocity vector by substracting the inverted normal from my direction vector (which is the vector to slide along the wall) and I add this vector to my new Player position and recalculate the direction vector (in case I have multiple collisions). I know I am missing some step but I can't seem to figure it out. Here is my code for the collision detection (run every frame): Vector direction; Vector newPos(camera.GetOriginX(), camera.GetOriginY(), camera.GetOriginZ()); direction = newPos - oldPos; // Direction vector // Check for collision with new position for(int i = 0; i < NUM_OBJECTS; i++) { Vector normal = objects[i].CheckCollision(newPos.x, newPos.y, newPos.z, direction.x, direction.y, direction.z); if(normal != Vector::NullVector()) { // Get inverse normal (direction STRAIGHT INTO wall) Vector invNormal = normal.Negative(); Vector wallDir = direction - invNormal; // We know INTO wall, and DIRECTION to wall. Substract these and you got slide WALL direction newPos = oldPos + wallDir; direction = newPos - oldPos; } } Any help would be greatly appreciated! FIX I eventually got things up and running how they should thanks to Krazy, I'll post the updated code listing in case someone else comes upon this problem! for(int i = 0; i < NUM_OBJECTS; i++) { Vector normal = objects[i].CheckCollision(newPos.x, newPos.y, newPos.z, direction.x, direction.y, direction.z); if(normal != Vector::NullVector()) { Vector invNormal = normal.Negative(); invNormal = invNormal * (direction * normal).Length(); // Change normal to direction's length and normal's axis Vector wallDir = direction - invNormal; newPos = oldPos + wallDir; direction = newPos - oldPos; } }

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  • How can I split Excel data from one row into multiple rows

    - by Lenny
    Good afternoon, Is there a way to split data from one row and store to separate rows? I have a large file that contains scheduling information and I'm trying to develop a list that comprises each combination of course, day, term and period per line. For example I have a file similiar to this: Crs:Sn Title Tchr TchrName Room Days Terms Periods 7014:01 English I 678 JUNG 300 M,T,W,R,F 3,4 2,3 1034:02 English II 123 MOORE 352 M,T,W,R,F 3 4 7144:02 Algebra 238 VYSOTSKY 352 M,T,W,R,F 3,4 3,4 0180:06 Pub Speaking 23 ROSEN 228 M,T,W,R,F 3,4 5 7200:03 PE I 244 HARILAOU GYM 4 M,T,W,R,F 1,2,3 3 2101:01 Physics/Lab 441 JONES 348 M,T,W,R,F 1,2,3,4 2,3 Should extract to this in an excel file: Crs:Sn Title Tchr# Tchr Room Days Terms Period 7014:01 English I 678 JUNG 300 M 3 2 7014:01 English I 678 JUNG 300 T 3 2 7014:01 English I 678 JUNG 300 W 3 2 7014:01 English I 678 JUNG 300 R 3 2 7014:01 English I 678 JUNG 300 F 3 2 7014:01 English I 678 JUNG 300 M 4 2 7014:01 English I 678 JUNG 300 T 4 2 7014:01 English I 678 JUNG 300 W 4 2 7014:01 English I 678 JUNG 300 R 4 2 7014:01 English I 678 JUNG 300 F 4 2 7014:01 English I 678 JUNG 300 M 3 3 7014:01 English I 678 JUNG 300 T 3 3 7014:01 English I 678 JUNG 300 W 3 3 7014:01 English I 678 JUNG 300 R 3 3 7014:01 English I 678 JUNG 300 F 3 3 7014:01 English I 678 JUNG 300 M 4 3 7014:01 English I 678 JUNG 300 T 4 3 7014:01 English I 678 JUNG 300 W 4 3 7014:01 English I 678 JUNG 300 R 4 3 7014:01 English I 678 JUNG 300 F 4 3 1034:02 English II 123 MOORE 352 M 3 4 1034:02 English II 123 MOORE 352 T 3 4 1034:02 English II 123 MOORE 352 W 3 4 1034:02 English II 123 MOORE 352 R 3 4 1034:02 English II 123 MOORE 352 F 3 4 7144:02 Algebra 238 VYSOTSKY 352 M 3 3 7144:02 Algebra 238 VYSOTSKY 352 T 3 3 7144:02 Algebra 238 VYSOTSKY 352 W 3 3 7144:02 Algebra 238 VYSOTSKY 352 R 3 3 7144:02 Algebra 238 VYSOTSKY 352 F 3 3 7144:02 Algebra 238 VYSOTSKY 352 M 4 3 7144:02 Algebra 238 VYSOTSKY 352 T 4 3 7144:02 Algebra 238 VYSOTSKY 352 W 4 3 7144:02 Algebra 238 VYSOTSKY 352 R 4 3 7144:02 Algebra 238 VYSOTSKY 352 F 4 3 7144:02 Algebra 238 VYSOTSKY 352 M 3 4 7144:02 Algebra 238 VYSOTSKY 352 T 3 4 7144:02 Algebra 238 VYSOTSKY 352 W 3 4 7144:02 Algebra 238 VYSOTSKY 352 R 3 4 7144:02 Algebra 238 VYSOTSKY 352 F 3 4 7144:02 Algebra 238 VYSOTSKY 352 M 4 4 7144:02 Algebra 238 VYSOTSKY 352 T 4 4 7144:02 Algebra 238 VYSOTSKY 352 W 4 4 7144:02 Algebra 238 VYSOTSKY 352 R 4 4 7144:02 Algebra 238 VYSOTSKY 352 F 4 4 0180:06 Pub Speaking 23 ROSEN 228 M 3 5 0180:06 Pub Speaking 23 ROSEN 228 T 3 5 0180:06 Pub Speaking 23 ROSEN 228 W 3 5 0180:06 Pub Speaking 23 ROSEN 228 R 3 5 0180:06 Pub Speaking 23 ROSEN 228 F 3 5 0180:06 Pub Speaking 23 ROSEN 228 M 4 5 0180:06 Pub Speaking 23 ROSEN 228 T 4 5 0180:06 Pub Speaking 23 ROSEN 228 W 4 5 0180:06 Pub Speaking 23 ROSEN 228 R 4 5 0180:06 Pub Speaking 23 ROSEN 228 F 4 5 7200:03 PE I 244 HARILAOU GYM 4 M 1 3 7200:03 PE I 244 HARILAOU GYM 4 M 2 3 7200:03 PE I 244 HARILAOU GYM 4 M 3 3 7200:03 PE I 244 HARILAOU GYM 4 T 1 3 7200:03 PE I 244 HARILAOU GYM 4 T 2 3 7200:03 PE I 244 HARILAOU GYM 4 T 3 3 7200:03 PE I 244 HARILAOU GYM 4 W 1 3 7200:03 PE I 244 HARILAOU GYM 4 W 2 3 7200:03 PE I 244 HARILAOU GYM 4 W 3 3 7200:03 PE I 244 HARILAOU GYM 4 R 1 3 7200:03 PE I 244 HARILAOU GYM 4 R 2 3 7200:03 PE I 244 HARILAOU GYM 4 R 3 3 7200:03 PE I 244 HARILAOU GYM 4 F 1 3 7200:03 PE I 244 HARILAOU GYM 4 F 2 3 7200:03 PE I 244 HARILAOU GYM 4 F 3 3 2101:01 Physics/Lab 441 JONES 348 M 1 2 2101:01 Physics/Lab 441 JONES 348 M 2 2 2101:01 Physics/Lab 441 JONES 348 M 3 2 2101:01 Physics/Lab 441 JONES 348 M 4 2 2101:01 Physics/Lab 441 JONES 348 T 1 2 2101:01 Physics/Lab 441 JONES 348 T 2 2 2101:01 Physics/Lab 441 JONES 348 T 3 2 2101:01 Physics/Lab 441 JONES 348 T 4 2 2101:01 Physics/Lab 441 JONES 348 W 1 2 2101:01 Physics/Lab 441 JONES 348 W 2 2 2101:01 Physics/Lab 441 JONES 348 W 3 2 2101:01 Physics/Lab 441 JONES 348 W 4 2 2101:01 Physics/Lab 441 JONES 348 R 1 2 2101:01 Physics/Lab 441 JONES 348 R 2 2 2101:01 Physics/Lab 441 JONES 348 R 3 2 2101:01 Physics/Lab 441 JONES 348 R 4 2 2101:01 Physics/Lab 441 JONES 348 F 1 2 2101:01 Physics/Lab 441 JONES 348 F 2 2 2101:01 Physics/Lab 441 JONES 348 F 3 2 2101:01 Physics/Lab 441 JONES 348 F 4 2 2101:01 Physics/Lab 441 JONES 348 M 1 3 2101:01 Physics/Lab 441 JONES 348 M 2 3 2101:01 Physics/Lab 441 JONES 348 M 3 3 2101:01 Physics/Lab 441 JONES 348 M 4 3 2101:01 Physics/Lab 441 JONES 348 T 1 3 2101:01 Physics/Lab 441 JONES 348 T 2 3 2101:01 Physics/Lab 441 JONES 348 T 3 3 2101:01 Physics/Lab 441 JONES 348 T 4 3 2101:01 Physics/Lab 441 JONES 348 W 1 3 2101:01 Physics/Lab 441 JONES 348 W 2 3 2101:01 Physics/Lab 441 JONES 348 W 3 3 2101:01 Physics/Lab 441 JONES 348 W 4 3 2101:01 Physics/Lab 441 JONES 348 R 1 3 2101:01 Physics/Lab 441 JONES 348 R 2 3 2101:01 Physics/Lab 441 JONES 348 R 3 3 2101:01 Physics/Lab 441 JONES 348 R 4 3 2101:01 Physics/Lab 441 JONES 348 F 1 3 2101:01 Physics/Lab 441 JONES 348 F 2 3 2101:01 Physics/Lab 441 JONES 348 F 3 3 2101:01 Physics/Lab 441 JONES 348 F 4 3 I'm trying to avoid going line by line separating the data. I'm not well versed on the VBA functionality of Excel, but would like to get started using it. Any help would be greatly appreciated.

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  • Finding the centeroid of a polygon?

    - by user146780
    I have tried: for each vertex, add to total, divide by number of verities to get center. I'v also tried: Find the topmost, bottommost - get midpoint... find leftmost, rightmost, find midpoint. Both of these did not return the perfect center because I'm relying on the center to scale a polygon. I want to scale my polygons so I may put a border around them. What is the best way to find the centroid of a polygon given that the polygon may be concave, convex and have many many sides of various lengths. Thanks

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  • How to delete duplicate vectors within a multidimensional vector?

    - by David
    I have a vector of vectors: vector< vector<int> > BigVec; It contains an arbitrary number of vectors, each of an arbitrary size. I want to delete not duplicate elements of each vector, but any vectors that are the exact same as another. I don't need to preserve the order of the vectors so I can sort etc.. It should be a really simple problem to solve but I'm new to this, my (not-working) best effort: for (int i = 0; i < BigVec.size(); i++) { for (int j = 1; j < BigVec.size() ; j++ ) { if (BigVec[i][0] == BigVec [j][i]); { BigVec.erase(BigVec.begin() + j); i = 0; // because i get the impression deleting a j = 1; // vector messes up a simple iteration through } } } I think there might be a solution using Unique(), but I can't get that to work either.

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  • Why would bitmap outperform vector, as3?

    - by VideoDnd
    Why would bitmap outperform vector? My Flash is for a large Kiosk, with rich media requirements and must function accurately as a counter. I want to keep everything vector for scalability. When I did a simple FPS test, I noticed my Bitmap version performed perfectly, and the all vector file was noticeably slower. PLEASE EXPLAIN • vector performance• what graphic standards I can apply• solutions for using vector KIOSK TEST ANIMATION RESULTS • only text and bitmap perform well, not vector • background and clouds OK, but more layers slow it down

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  • Ray Generation Inconsistency

    - by Myx
    I have written code that generates a ray from the "eye" of the camera to the viewing plane some distance away from the camera's eye: R3Ray ConstructRayThroughPixel(...) { R3Point p; double increments_x = (lr.X() - ul.X())/(double)width; double increments_y = (ul.Y() - lr.Y())/(double)height; p.SetX( ul.X() + ((double)i_pos+0.5)*increments_x ); p.SetY( lr.Y() + ((double)j_pos+0.5)*increments_y ); p.SetZ( lr.Z() ); R3Vector v = p-camera_pos; R3Ray new_ray(camera_pos,v); return new_ray; } ul is the upper left corner of the viewing plane and lr is the lower left corner of the viewing plane. They are defined as follows: R3Point org = scene->camera.eye + scene->camera.towards * radius; R3Vector dx = scene->camera.right * radius * tan(scene->camera.xfov); R3Vector dy = scene->camera.up * radius * tan(scene->camera.yfov); R3Point lr = org + dx - dy; R3Point ul = org - dx + dy; Here, org is the center of the viewing plane with radius being the distance between the viewing plane and the camera eye, dx and dy are the displacements in the x and y directions from the center of the viewing plane. The ConstructRayThroughPixel(...) function works perfectly for a camera whose eye is at (0,0,0). However, when the camera is at some different position, not all needed rays are produced for the image. Any suggestions what could be going wrong? Maybe something wrong with my equations? Thanks for the help.

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  • How to shrink-to-fit an std::vector in a memory-efficient way?

    - by dehmann
    I would like to 'shrink-to-fit' an std::vector, to reduce its capacity to its exact size, so that additional memory is freed. The standard trick seems to be the one described here: template< typename T, class Allocator > void shrink_capacity(std::vector<T,Allocator>& v) { std::vector<T,Allocator>(v.begin(),v.end()).swap(v); } The whole point of shrink-to-fit is to save memory, but doesn't this method first create a deep copy and then swaps the instances? So at some point -- when the copy is constructed -- the memory usage is doubled? If that is the case, is there a more memory-friendly method of shrink-to-fit? (In my case the vector is really big and I cannot afford to have both the original plus a copy of it in memory at any time.)

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  • Is there a version of the removeElement function in Go for the vector package like Java has in its V

    - by Brian T Hannan
    I am porting over some Java code into Google's Go language and I converting all code except I am stuck on just one part after an amazingly smooth port. My Go code looks like this and the section I am talking about is commented out: func main() { var puzzleHistory * vector.Vector; puzzleHistory = vector.New(0); var puzzle PegPuzzle; puzzle.InitPegPuzzle(3,2); puzzleHistory.Push(puzzle); var copyPuzzle PegPuzzle; var currentPuzzle PegPuzzle; currentPuzzle = puzzleHistory.At(0).(PegPuzzle); isDone := false; for !isDone { currentPuzzle = puzzleHistory.At(0).(PegPuzzle); currentPuzzle.findAllValidMoves(); for i := 0; i < currentPuzzle.validMoves.Len(); i++ { copyPuzzle.NewPegPuzzle(currentPuzzle.holes, currentPuzzle.movesAlreadyDone); copyPuzzle.doMove(currentPuzzle.validMoves.At(i).(Move)); // There is no function in Go's Vector that will remove an element like Java's Vector //puzzleHistory.removeElement(currentPuzzle); copyPuzzle.findAllValidMoves(); if copyPuzzle.validMoves.Len() != 0 { puzzleHistory.Push(copyPuzzle); } if copyPuzzle.isSolutionPuzzle() { fmt.Printf("Puzzle Solved"); copyPuzzle.show(); isDone = true; } } } } If there is no version available, which I believe there isn't ... does anyone know how I would go about implementing such a thing on my own?

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  • Finding the centroid of a polygon?

    - by user146780
    I have tried: for each vertex, add to total, divide by number of verities to get center. I'v also tried: Find the topmost, bottommost - get midpoint... find leftmost, rightmost, find midpoint. Both of these did not return the perfect center because I'm relying on the center to scale a polygon. I want to scale my polygons so I may put a border around them. What is the best way to find the centroid of a polygon given that the polygon may be concave, convex and have many many sides of various lengths. Thanks

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  • Is the old vector get cleared? If yes, how and when?

    - by user180866
    I have the following code: void foo() { vector<double> v(100,1); // line 1 // some code v = vector<double>(200,2); // line 2 // some code } what happened to the vector of size 100 after the second line? Is it gets cleared by itself? If the answer is yes, how and when it is cleared? By the way, is there any other "easy and clean" ways to change the vector as in line 2? I don't want things like v.resize(200); for (int i=0; i<200; i++) v[i] = 2;

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  • C++ vector<T>::iterator operator +

    - by Tom
    Hi, Im holding an iterator that points to an element of a vector, and I would like to compare it to the next element of the vector. Here is what I have Class Point{ public: float x,y; } //Somewhere in my code I do this vector<Point> points = line.getPoints(); foo (points.begin(),points.end()); where foo is: void foo (Vector<Point>::iterator begin,Vector<Point>::iterator end) { std::Vector<Point>::iterator current = begin; for(;current!=end-1;++current) { std::Vector<Point>::iterator next = current + 1; //Compare between current and next. } } I thought that this would work, but current + 1 is not giving me the next element of the vector. I though operator+ was the way to go, but doesnt seem so. Is there a workaround on this? THanks

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  • fastest engine to convert PDF into PNG

    - by skyde
    I would like to know which of the opensource PDF engine can convert a pdf into a image the fastest. I don't care about the quality of the result (antialiasing ...) For my project it need to be very very fast. I would probably need to build my own but i dont wan't to start from scratch.

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  • How to restrict the range of elements of C++ STL vector?

    - by cambr
    vector<int> l; for(int i=0;i<10;i++){ l.push_back(i); } I want the vector to only be able to store numbers from a specified range (or set). How can that be done, in general? In particular, I want to restrict the vector to beonly be able to store single digits. So, if I do a l[9]++, it should give me an error or warn me. (because 10 is not a single digit number). Similarly, l[0]-- should warn me. Is there a way to do this using C++ STL vector?

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  • Attribute vector emptying itself

    - by ravloony
    Hello, I have two classes, derived from a common class. The common class has a pure virtual function called execute(), which is implemented in both derived classes. In the inherited class I have an attribute which is a vector. In both execute() methods I overwrite this vector with a result. I access both classes from a vector of pointers to their objects. The problem is when I try to access the result vector form outside the objects. In one case I can get the elements (which are simply pointers), in the other I cannot, the vector is empty. Code: class E; class A{ protected: vector<E*> _result; public: virtual void execute()=0; vector<E*> get_result(); }; vector<E*> A::get_result() { return _result; } class B : public A { public: virtual void execute(); }; B::execute() { //... _result = tempVec; return; } class C : public A { public: virtual void execute(); }; C::execute() { //different stuff to B _result = tempvec; return; } main() { B* b = new B(); C* c = new C(); b->execute(); c->execute(); b->get_result();//returns full vector c->get_result(); //returns empty vector!! } I have no idea what is going on here... I have tried filling _result by hand from a temp vector in the offending class, doing the same with vector::assign(), nothing works. And the other object works perfectly. I must be missing something.... Any help would be greatly appreciated.

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  • which is better in general, map or vector in c++?

    - by tsubasa
    As I know that accessing an element in vector takes constant time while in map takes logarithmic time. However, storing a map takes less memory than storing a vector. Therefore, I want to ask which one is better in general? I'm considering using one of those two in my program, which has about 1000 elements. I plan to use 3 dimensional vector, which would take 1000x1000x1000 elements.

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  • Does std::vector change its address? How to avoid

    - by kunigami
    Since vector elements are stored contiguously, I guess it may not have the same address after some push_back's , because the initial allocated space could not suffice. I'm working on a code where I need a reference to an element in a vector, like: int main(){ vector<int> v; v.push_back(1); int *ptr = &v[0]; for(int i=2; i<100; i++) v.push_back(i); cout << *ptr << endl; //? return 0; } But it's not necessarily true that ptr contains a reference to v[0], right? How would be a good way to guarantee it? My first idea would be to use a vector of pointers and dynamic allocation. I'm wondering if there's an easier way to do that? PS.: Actually I'm using a vector of a class instead of int, but I think the issues are the same.

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  • How to initialize std::vector from C-style array?

    - by dehmann
    What is the cheapest way to initialize a std::vector from a C-style array? Example: In the following class, I have a vector, but due to outside restrictions, the data will be passed in as C-style array: class Foo { std::vector<double> w_; public: void set_data(double* w, int len){ // how to cheaply initialize the std::vector? } Obviously, I can call w_.resize() and then loop over the elements, or call std::copy(). Are there any better methods?

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  • Resultant Vector Algorithm for 2D Collisions

    - by John
    I am making a Pong based game where a puck hits a paddle and bounces off. Both the puck and the paddles are Circles. I came up with an algorithm to calculate the resultant vector of the puck once it meets a paddle. The game seems to function correctly but I'm not entirely sure my algorithm is correct. Here are my variables for the algorithm: Given: velocity = the magnitude of the initial velocity of the puck before the collision x = the x coordinate of the puck y = the y coordinate of the puck moveX = the horizontal speed of the puck moveY = the vertical speed of the puck otherX = the x coordinate of the paddle otherY = the y coordinate of the paddle piece.horizontalMomentum = the horizontal speed of the paddle before it hits the puck piece.verticalMomentum = the vertical speed of the paddle before it hits the puck slope = the direction, in radians, of the puck's velocity distX = the horizontal distance between the center of the puck and the center of the paddle distY = the vertical distance between the center of the puck and the center of the paddle Algorithm solves for: impactAngle = the angle, in radians, of the angle of impact. newSpeedX = the speed of the resultant vector in the X direction newSpeedY = the speed of the resultant vector in the Y direction Here is the code for my algorithm: int otherX = piece.x; int otherY = piece.y; double velocity = Math.sqrt((moveX * moveX) + (moveY * moveY)); double slope = Math.atan(moveX / moveY); int distX = x - otherX; int distY = y - otherY; double impactAngle = Math.atan(distX / distY); double newAngle = impactAngle + slope; int newSpeedX = (int)(velocity * Math.sin(newAngle)) + piece.horizontalMomentum; int newSpeedY = (int)(velocity * Math.cos(newAngle)) + piece.verticalMomentum; for those who are not program savvy here is it simplified: velocity = v(moveX² + moveY²) slope = arctan(moveX / moveY) distX = x - otherX distY = y - otherY impactAngle = arctan(distX / distY) newAngle = impactAngle + slope newSpeedX = velocity * sin(newAngle) + piece.horizontalMomentum newSpeedY = velocity * cos(newAngle) + piece.verticalMomentum My Question: Is this algorithm correct? Is there an easier/simpler way to do what I'm trying to do?

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  • How to print a rendered website to pdf or vector graphics?

    - by Lo Sauer
    This is a crucial question to many: Searching the web, I have found several command line tools that allow you to convert a HTML-document to a PDF-document, however they all seem to use their own, and rather incomplete rendering engine, resulting in poor quality How can you print the rendered output of a modern web-browser to pdf, (and/or svg) whilst retaining as much vector graphics as possible? There is a solution called: webkit-pdf (which renders everything to bitmap graphics) I am looking for options, alternatives, suggestions perhaps even a printer-driver or webservices? Thanks

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  • C++ STL: How to iterate vector while requiring access to element and its index?

    - by Ashwin
    I frequently find myself requiring to iterate over STL vectors. While I am doing this I require access to both the vector element and its index. I used to do this as: typedef std::vector<Foo> FooVec; typedef FooVec::iterator FooVecIter; FooVec fooVec; int index = 0; for (FooVecIter i = fooVec.begin(); i != fooVec.end(); ++i, ++index) { Foo& foo = *i; if (foo.somethingIsTrue()) // True for most elements std::cout << index << ": " << foo << std::endl; } After discovering BOOST_FOREACH, I shortened this to: typedef std::vector<Foo> FooVec; FooVec fooVec; int index = -1; BOOST_FOREACH( Foo& foo, fooVec ) { ++index; if (foo.somethingIsTrue()) // True for most elements std::cout << index << ": " << foo << std::endl; } Is there a better or more elegant way to iterate over STL vectors when both reference to the vector element and its index is required? I am aware of the alternative: for (int i = 0; i < fooVec.size(); ++i) But I keep reading about how it is not a good practice to iterate over STL containers like this.

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