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  • Problems Allocating Objects of Derived Class Where Base Class has Abstract Virtual Functions

    - by user1743901
    I am trying to get this Zombie/Human agent based simulation running, but I am having problems with these derived classes (Human and Zombie) who have parent class "Creature". I have 3 virtual functions declared in "Creature" and all three of these are re-declared AND DEFINED in both "Human" and "Zombie". But for some reason when I have my program call "new" to allocate memory for objects of type Human or Zombie, it complains about the virtual functions being abstract. Here's the code: definitions.h #ifndef definitions_h #define definitions_h class Creature; class Item; class Coords; class Grid { public: Creature*** cboard; Item*** iboard; int WIDTH; int HEIGHT; Grid(int WIDTHVALUE, int HEIGHTVALUE); void FillGrid(); //initializes grid object with humans and zombies void Refresh(); //calls Creature::Die(),Move(),Attack(),Breed() on every square void UpdateBuffer(char** buffer); bool isEmpty(int startx, int starty, int dir); char CreatureType(int xcoord, int ycoord); char CreatureType(int startx, int starty, int dir); }; class Random { public: int* rptr; void Print(); Random(int MIN, int MAX, int LEN); ~Random(); private: bool alreadyused(int checkthis, int len, int* rptr); bool isClean(); int len; }; class Coords { public: int x; int y; int MaxX; int MaxY; Coords() {x=0; y=0; MaxX=0; MaxY=0;} Coords(int X, int Y, int WIDTH, int HEIGHT) {x=X; y=Y; MaxX=WIDTH; MaxY=HEIGHT; } void MoveRight(); void MoveLeft(); void MoveUp(); void MoveDown(); void MoveUpRight(); void MoveUpLeft(); void MoveDownRight(); void MoveDownLeft(); void MoveDir(int dir); void setx(int X) {x=X;} void sety(int Y) {y=Y;} }; class Creature { public: bool alive; Coords Location; char displayletter; Creature() {Location.x=0; Location.y=0;} Creature(int i, int j) {Location.setx(i); Location.sety(j);} virtual void Attack() =0; virtual void AttackCreature(Grid G, int attackdirection) =0; virtual void Breed() =0; void Die(); void Move(Grid G); int DecideSquare(Grid G); void MoveTo(Grid G, int dir); }; class Human : public Creature { public: bool armed; //if armed, chances of winning fight increased for next fight bool vaccinated; //if vaccinated, no chance of getting infected int bitecount; //if a human is bitten, bite count is set to a random number int breedcount; //if a human goes x steps without combat, will breed if next to a human int starvecount; //if a human does not eat in x steps, will die Human() {displayletter='H';} Human(int i, int j) {displayletter='H';} void Attack(Grid G); void AttackCreature(Grid G, int attackdirection); void Breed(Grid G); //will breed after x steps and next to human int DecideAttack(Grid G); }; class Zombie : public Creature { public: Zombie() {displayletter='Z';} Zombie(int i, int j) {displayletter='Z';} void Attack(Grid G); void AttackCreature(Grid G, int attackdirection); void Breed() {} //does nothing int DecideAttack(Grid G); void AttackCreature(Grid G, int attackdirection); }; class Item { }; #endif definitions.cpp #include <cstdlib> #include "definitions.h" Random::Random(int MIN, int MAX, int LEN) //constructor { len=LEN; rptr=new int[LEN]; //allocate array of given length for (int i=0; i<LEN; i++) { int random; do { random = rand() % (MAX-MIN+1) + MIN; } while (alreadyused(random,LEN,rptr)); rptr[i]=random; } } bool Random::alreadyused(int checkthis, int len, int* rptr) { for (int i=0; i<len; i++) { if (rptr[i]==checkthis) return 1; } return 0; } Random::~Random() { delete rptr; } Grid::Grid(int WIDTHVALUE, int HEIGHTVALUE) { WIDTH = WIDTHVALUE; HEIGHT = HEIGHTVALUE; //builds 2d array of creature pointers cboard = new Creature**[WIDTH]; for(int i=0; i<WIDTH; i++) { cboard[i] = new Creature*[HEIGHT]; } //builds 2d array of item pointers iboard = new Item**[WIDTH]; for (int i=0; i<WIDTH; i++) { iboard[i] = new Item*[HEIGHT]; } } void Grid::FillGrid() { /* For each creature pointer in grid, randomly selects whether to initalize as zombie, human, or empty square. This methodology can be changed to initialize different creature types with different probabilities */ int random; for (int i=0; i<WIDTH; i++) { for (int j=0; j<HEIGHT; j++) { Random X(1,100,1); //create a single random integer from [1,100] at X.rptr random=*(X.rptr); if (random < 20) cboard[i][j] = new Human(i,j); else if (random < 40) cboard[i][j] = new Zombie(i,j); else cboard[i][j] = NULL; } } //at this point every creature pointer should be pointing to either //a zombie, human, or NULL with varying probabilities } void Grid::UpdateBuffer(char** buffer) { for (int i=0; i<WIDTH; i++) { for (int j=0; j<HEIGHT; j++) { if (cboard[i][j]) buffer[i][j]=cboard[i][j]->displayletter; else buffer[i][j]=' '; } } } bool Grid::isEmpty(int startx, int starty, int dir) { Coords StartLocation(startx,starty,WIDTH,HEIGHT); switch(dir) { case 1: StartLocation.MoveUp(); if (cboard[StartLocation.x][StartLocation.y]) return 0; case 2: StartLocation.MoveUpRight(); if (cboard[StartLocation.x][StartLocation.y]) return 0; case 3: StartLocation.MoveRight(); if (cboard[StartLocation.x][StartLocation.y]) return 0; case 4: StartLocation.MoveDownRight(); if (cboard[StartLocation.x][StartLocation.y]) return 0; case 5: StartLocation.MoveDown(); if (cboard[StartLocation.x][StartLocation.y]) return 0; case 6: StartLocation.MoveDownLeft(); if (cboard[StartLocation.x][StartLocation.y]) return 0; case 7: StartLocation.MoveLeft(); if (cboard[StartLocation.x][StartLocation.y]) return 0; case 8: StartLocation.MoveUpLeft(); if (cboard[StartLocation.x][StartLocation.y]) return 0; } return 1; } char Grid::CreatureType(int xcoord, int ycoord) { if (cboard[xcoord][ycoord]) //if there is a creature at location xcoord,ycoord return (cboard[xcoord][ycoord]->displayletter); else //if pointer at location xcoord,ycoord is null, return null char return '\0'; } char Grid::CreatureType(int startx, int starty, int dir) { Coords StartLocation(startx,starty,WIDTH,HEIGHT); switch(dir) { case 1: StartLocation.MoveUp(); if (cboard[StartLocation.x][StartLocation.y]) return (cboard[StartLocation.x][StartLocation.y]->displayletter); case 2: StartLocation.MoveUpRight(); if (cboard[StartLocation.x][StartLocation.y]) return (cboard[StartLocation.x][StartLocation.y]->displayletter); case 3: StartLocation.MoveRight(); if (cboard[StartLocation.x][StartLocation.y]) return (cboard[StartLocation.x][StartLocation.y]->displayletter); case 4: StartLocation.MoveDownRight(); if (cboard[StartLocation.x][StartLocation.y]) return (cboard[StartLocation.x][StartLocation.y]->displayletter); case 5: StartLocation.MoveDown(); if (cboard[StartLocation.x][StartLocation.y]) return (cboard[StartLocation.x][StartLocation.y]->displayletter); case 6: StartLocation.MoveDownLeft(); if (cboard[StartLocation.x][StartLocation.y]) return (cboard[StartLocation.x][StartLocation.y]->displayletter); case 7: StartLocation.MoveLeft(); if (cboard[StartLocation.x][StartLocation.y]) return (cboard[StartLocation.x][StartLocation.y]->displayletter); case 8: StartLocation.MoveUpLeft(); if (cboard[StartLocation.x][StartLocation.y]) return (cboard[StartLocation.x][StartLocation.y]->displayletter); } //if function hasn't returned by now, square being looked at is pointer to null return '\0'; //return null char } void Coords::MoveRight() {(x==MaxX)? (x=0):(x++);} void Coords::MoveLeft() {(x==0)? (x=MaxX):(x--);} void Coords::MoveUp() {(y==0)? (y=MaxY):(y--);} void Coords::MoveDown() {(y==MaxY)? (y=0):(y++);} void Coords::MoveUpRight() {MoveUp(); MoveRight();} void Coords::MoveUpLeft() {MoveUp(); MoveLeft();} void Coords::MoveDownRight() {MoveDown(); MoveRight();} void Coords::MoveDownLeft() {MoveDown(); MoveLeft();} void Coords::MoveDir(int dir) { switch(dir) { case 1: MoveUp(); break; case 2: MoveUpRight(); break; case 3: MoveRight(); break; case 4: MoveDownRight(); break; case 5: MoveDown(); break; case 6: MoveDownLeft(); break; case 7: MoveLeft(); break; case 8: MoveUpLeft(); break; case 0: break; } } void Creature::Move(Grid G) { int movedir=DecideSquare(G); MoveTo(G,movedir); } int Creature::DecideSquare(Grid G) { Random X(1,8,8); //X.rptr now points to 8 unique random integers from [1,8] for (int i=0; i<8; i++) { int dir=X.rptr[i]; if (G.isEmpty(Location.x,Location.y,dir)) return dir; } return 0; } void Creature::MoveTo(Grid G, int dir) { Coords OldLocation=Location; Location.MoveDir(dir); G.cboard[Location.x][Location.y]=this; //point new location to this creature G.cboard[OldLocation.x][OldLocation.y]=NULL; //point old location to NULL } void Creature::Die() { if (!alive) { delete this; this=NULL; } } void Human::Breed(Grid G) { if (!breedcount) { Coords BreedLocation=Location; Random X(1,8,8); for (int i=0; i<8; i++) { BreedLocation.MoveDir(X.rptr[i]); if (!G.cboard[BreedLocation.x][BreedLocation.y]) { G.cboard[BreedLocation.x][BreedLocation.y])=new Human(BreedLocation.x,BreedLocation.y); return; } } } } int Human::DecideAttack(Grid G) { Coords AttackLocation=Location; Random X(1,8,8); int attackdir; for (int i=0; i<8; i++) { attackdir=X.rptr[i]; switch(G.CreatureType(Location.x,Location.y,attackdir)) { case 'H': break; case 'Z': return attackdir; case '\0': break; default: break; } } return 0; //no zombies! } int AttackRoll(int para1, int para2) { //outcome 1: Zombie wins, human dies //outcome 2: Human wins, zombie dies //outcome 3: Human wins, zombie dies, but human is bitten Random X(1,100,1); int roll= *(X.rptr); if (roll < para1) return 1; else if (roll < para2) return 2; else return 3; } void Human::AttackCreature(Grid G, int attackdirection) { Coords AttackLocation=Location; AttackLocation.MoveDir(attackdirection); int para1=33; int para2=33; if (vaccinated) para2=101; //makes attackroll > para 2 impossible, never gets infected if (armed) para1-=16; //reduces chance of zombie winning fight int roll=AttackRoll(para1,para2); //outcome 1: Zombie wins, human dies //outcome 2: Human wins, zombie dies //outcome 3: Human wins, zombie dies, but human is bitten switch(roll) { case 1: alive=0; //human (this) dies return; case 2: G.cboard[AttackLocation.x][AttackLocation.y]->alive=0; return; //zombie dies case 3: G.cboard[AttackLocation.x][AttackLocation.y]->alive=0; //zombie dies Random X(3,7,1); //human is bitten bitecount=*(X.rptr); return; } } int Zombie::DecideAttack(Grid G) { Coords AttackLocation=Location; Random X(1,8,8); int attackdir; for (int i=0; i<8; i++) { attackdir=X.rptr[i]; switch(G.CreatureType(Location.x,Location.y,attackdir)) { case 'H': return attackdir; case 'Z': break; case '\0': break; default: break; } } return 0; //no zombies! } void Zombie::AttackCreature(Grid G, int attackdirection) { int reversedirection; if (attackdirection < 9 && attackdirection>0) { (attackdirection<5)? (reversedirection=attackdirection+4):(reversedirection=attackdirection-4); } else reversedirection=0; //this should never happen //when a zombie attacks a human, the Human::AttackZombie() function is called //in the "reverse" direction, utilizing that function that has already been written Coords ZombieLocation=Location; Coords HumanLocation=Location; HumanLocation.MoveDir(attackdirection); if (G.cboard[HumanLocation.x][HumanLocation.y]) //if there is a human there, which there should be G.cboard[HumanLocation.x][HumanLocation.y]->AttackCreature(G,reversedirection); } void Zombie::Attack(Grid G) { int attackdirection=DecideAttack(G); AttackCreature(G,attackdirection); } main.cpp #include <cstdlib> #include <iostream> #include "definitions.h" using namespace std; int main(int argc, char *argv[]) { Grid G(500,500); system("PAUSE"); return EXIT_SUCCESS; }

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  • Constrain generic extension method to base types and string

    - by hitch
    I want to have an extension method for XElement/XAttribute that allows me to apply a "ValueOrDefault" logic - perhaps with various slightly different implementations: ValueOrNull, ValueOrDefault, NumericValueOrDefault (which validates if the value is numeric), but I want to constrain these methods so that they can only work with ValueTypes or String (i.e. it does not really make sense to use any other reference types. Is it possible to do this with one implementation of each method, or will I have to have one where the constraint is "Structure" and one where the constraint is "String" - if I combine Structure and String in the generic constraint, I get the error : 'Structure' constraint and a specific class type constraint cannot be combined. An example of the current method implementation is as follows: <Extension()> _ Public Function ValueOrDefault(Of T As {Structure})(ByVal xe As XElement, ByVal defaultValue As T) As T If xe Is Nothing or xe.Value = "" Then Return defaultValue End If Return CType(Convert.ChangeType(xe.Value, GetType(T)), T) End Function

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  • How to debug Ruby base methods in Netbeans ?

    - by Bragaadeesh
    Hi, I am able to debug my ruby program. At times, I would want to go inside the library methods and see what is happening. How to achieve it in Ruby. For example, [ 3, 1, 7, 0 ].sort i would want to go inside the sort method and see how that works lively. In Java+Eclipse this is possible, all I have to do is to attach the source of Foundation classes in Eclipse. Is it possible in Ruby with Netbeans as IDE? Thanks

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  • How to easily substitute a Base class

    - by JTom
    Hi, I have the following hierarchy of classes class classOne { virtual void abstractMethod() = 0; }; class classTwo : public classOne { }; class classThree : public classTwo { }; All classOne, classTwo and classThree are abstract classes, and I have another class that is defining the pure virtual methods class classNonAbstract : public classThree { void abstractMethod(); // Couple of new methods void doIt(); void doItToo(); }; And right now I need it differently...I need it like class classNonAbstractOne : public classOne { void abstractMethod(); // Couple of new methods void doIt(); void doItToo(); }; class classNonAbstractTwo : public classTwo { void abstractMethod(); // Couple of new methods void doIt(); void doItToo(); }; and class classNonAbstractThree : public classThree { void abstractMethod(); // Couple of new methods void doIt(); void doItToo(); }; But all the nonAbstract classes have the same new methods, with the same code...and I would like to avoid copying all the methods and it's code to every nonAbstract class. How could I accomplish that? Hopefully it's understandable...

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  • cached data base

    - by radi
    hi , in my project i need a tow tables each of it has about 2000 row , i want my application to be speed so my db should load into memory (cached) when the app start and before it close the db have to be saved on the disk . i am using java and i want to use sql

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  • drop down and post data to data base

    - by DAFFODIL
    This is a form which retrieves data from db and displays them in table. At the beginning of each row there will be a check box. If there are 10 rows fetched, I ii check 5 rows and insert them in to diff db but here when, I click drop down box data is getting in to db automatically,bcoz I use onchange event. Any alternative to prevent this to happen. Data should be inserted only when, I click submit button. Any help will be appreciated <?php $con = mysql_connect("localhost","root",""); if (!$con) { die('Could not connect: ' . mysql_error()); } mysql_select_db("form1", $con); error_reporting(E_ALL ^ E_NOTICE); $nam=$_REQUEST['select1']; $row=mysql_query("select * from inv where name='$nam'"); while($row1=mysql_fetch_array($row)) { $Name=$row1['Name']; $Address =$row1['Address']; $City=$row1['City']; $Pincode=$row1['Pincode']; $No=$row1['No']; $Date=$row1['Date']; $DCNo=$row1['DCNo']; $DcDate=$row1['DcDate']; $YourOrderNo=$row1['YourOrderNo']; $OrderDate=$row1['OrderDate']; $VendorCode=$row1['VendorCode']; $SNo=$row1['SNo']; $descofgoods=$row1['descofgoods']; $Qty=$row1['Qty']; $Rate=$row1['Rate']; $Amount=$row1['Amount']; } ?> <!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd"> <html xmlns="http://www.w3.org/1999/xhtml"> <head> <meta http-equiv="Content-Type" content="text/html; charset=iso-8859-1" /> <title>Untitled Document</title> <script type="text/javascript"> function ram(id) { var q=document.getElementById('qty_'+id).value; var r=document.getElementById('rate_'+id).value; document.getElementById('amt_'+id).value=q*r; } </script> </head> <body> <form id="form1" name="form1" method="post" action=""> <table width="1315" border="0"> <script type="text/javascript"> function g() { form1.submit(); } </script> <tr> <th>Name</th> <th align="left"><select name="select1" onchange="g();"> <option value="" selected="selected">select</option> <?php $row=mysql_query("select Name from inv "); while($row1=mysql_fetch_array($row)) { ?> <option value="<?php echo $row1['Name'];?>"><?php echo $row1['Name'];?></option> <?php } ?> </select></th> </tr> <tr> <th>Address</th> <th align="left"><textarea name="Address"><?php echo $Address;?></textarea></th> </tr> <tr> <th>City</th> <th align="left"><input type="text" name="City" value='<?php echo $City;?>' /></th> </tr> <tr> <th>Pincode</th> <th align="left"><input type="text" name="Pincode" value='<?php echo $Pincode;?>'></th> </tr> <tr> <th>No</th> <th align="left"><input type="text" name="No2" value='<?php echo $No;?>' readonly="" /></th> </tr> <tr> <th>Date</th> <th align="left"><input type="text" name="Date" value='<?php echo $Date;?>' /></th> </tr> <tr> <th>DCNo</th> <th align="left"><input type="text" name="DCNo" value='<?php echo $DCNo;?>' readonly="" /></th> </tr> <tr> <th>DcDate:</th> <th align="left"><input type="text" name="DcDate" value='<?php echo $DcDate;?>' /></th> </tr> <tr> <th>YourOrderNo</th> <th align="left"><input type="text" name="YourOrderNo" value='<?php echo $YourOrderNo;?>' readonly="" /></th> </tr> <tr> <th>OrderDate</th> <th align="left"><input type="text" name="OrderDate" value='<?php echo $OrderDate;?>' /></th> </tr> <tr> <th width="80">VendorCode</th> <th width="1225" align="left"><input type="text" name="VendorCode" value='<?php echo $VendorCode;?>' readonly="" /></th> </tr> </table> <table width="1313" border="0"> <tr> <td width="44">&nbsp;</td> <td width="71">SNO</td> <td width="527">DESCRIPTION</td> <td width="214">QUANTITY</td> <td width="214">RATE/UNIT</td> <td width="217">AMOUNT</td> </tr> <?php $i=1; $row=mysql_query("select * from inv where Name='$nam'"); while($row1=mysql_fetch_array($row)) { $SNo=$row1['SNo']; $descofgoods=$row1['descofgoods']; $Qty=$row1['Qty']; $Rate=$row1['Rate']; $Amount=$row1['Amount']; ?> <tr> <td><input type="checkbox" name="checkbox" value="checkbox" checked="checked"/></td> <td><input type="text" name="No[<?php echo $i?>]" value='<?php echo $SNo;?>' readonly=""/></td> <td><input type="text" name="descofgoods[<?php echo $i?>]" value='<?php echo $descofgoods;?>' /></td> <td><input type="text" name="qty[<?php echo $i?>]" maxlength="50000000" id="qty_<?PHP echo($i) ?>"/></td> <td><input type="text" name="Rate[<?php echo $i?>]" value='<?php echo $Rate;?>' id="rate_<?PHP echo($i) ?>" onclick="ram('<?PHP echo($i) ?>')";></td> <td><input type="text" name="Amount[<?php echo $i?>]" id="amt_<?PHP echo($i) ?>"/></td> </tr> <?php $i++;} ?> <tr> <td><input type="submit" value="submit" header("location:values to be brought for print page.php");/></td> </tr> </table> <label></label> </form> </body> </html> <?php /*error_reporting(E_ALL ^ E_NOTICE); $con = mysql_connect("localhost","root",""); if (!$con) { die('Could not connect: ' . mysql_error()); } mysql_select_db("form1", $con); /*if(checked=checkbox) { mysql_query="INSERT INTO invo (Name, Address, City, Pincode, No, Date, DCNo, DcDate, YourOrderNo, OrderDate, VendorCode, SNo, descofgoods, Qty, Rate, Amount) VALUES ('$_POST[Name]','$_POST[Address]','$_POST[City]','$_POST[Pincode]','$_POST[No]','$_POST[Date]','$_POST[DCNo]','$_POST[DcDate]','$_POST[YourOrderNo]','$_POST[OrderDate]','$_POST[VendorCode]','$_POST[SNo]','$_POST[descofgoods]','$_POST[qty]','$_POST[Rate]','$_POST[Amount]')"; } else { header("location:values to be brought for print page.php"); }*/ header("ins.php"); ?>

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  • Is AutoMapper able to auto resolve types base on existing maps

    - by Chi Chan
    I have the following code: [SetUp] public void SetMeUp() { Mapper.CreateMap<SourceObject, DestinationObject>(); } [Test] public void Testing() { var source = new SourceObject {Id = 123}; var destination1 = Mapper.Map<SourceObject, DestinationObject>(source); var destination2 = Mapper.Map<ObjectBase, ObjectBase>(source); //Works Assert.That(destination1.Id == source.Id); //Fails, gives the same object back Assert.That(destination2 is DestinationObject); } public class ObjectBase { public int Id { get; set; } } public class SourceObject : ObjectBase { } public class DestinationObject : ObjectBase { } So basically, I want AutoMapper to automatically resolve the destination type to "DestinationObject" based on the existing Maps set up in AutoMapper. Is there a way to achieve this?

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  • Add custom Model Binders for derived objects and their base

    - by mare
    My class diagram: BaseContentClass Page inherits BaseContentClass Tab inherits BaseContentClass ... If I do this ModelBinders.Binders.Add(typeof(BaseContentObject), new BaseContentObjectCommonPropertiesBinder()); then when in controller action parameter of type Tab appears, custom model binder is not fired. It gets fired if I do this: ModelBinders.Binders.Add(typeof(Tab), new BaseContentObjectCommonPropertiesBinder()); But I don't want to go writing "n" number of Add statements in my global.asax.cs to associate all the derived classes with my custom model binder, do I? I don't know if I have any other option.

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  • Incorrect new Uri(base, relative) behaviour in .NET

    - by dr. evil
    When you create a new Uri like this: New Uri(New Uri("http://example.com/test.php"),"?x=y") it returns: http://example.com/?x=y It was supposed to return: http://example.com/test.php?x=y according to the every major browser out there (I'm not quite sure what RFC says though). Is this is a bug or is there any other function out there which behaves correctly, also what's the best way to fix it without reinventing the wheel?

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  • Find user defined functions and their usage in a massive code base

    - by Frenck
    Hi, I'm currently working with an massive PHP codebase, witch is completely undocumented. Here's the deal. All of the PHP code is included every page call. They build a simple include all kinda function that scan's the directory and includes all PHP files it can find. It works recursively for all the subfolders. I would like to know what functions are used in what files and from which files those functions came. I need to know this in order to switch to normale includes. Also it gives me more information about not used functions and files (since it a really old and big codebase, there is a lot of legacy in it). It there a tool or something for PHP that can check this kind of stuff in a codebase?

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  • Is extending a base class with non-virtual destructor dangerous in C++

    - by Akusete
    Take the following code class A { }; class B : public A { }; class C : public A { int x; }; int main (int argc, char** argv) { A* b = new B(); A* c = new C(); //in both cases, only ~A() is called, not ~B() or ~C() delete b; //is this ok? delete c; //does this line leak memory? return 0; } when calling delete on a class with a non-virtual destructor with member functions (like class C), can the memory allocator tell what the proper size of the object is? If not, is memory leaked? Secondly, if the class has no member functions, and no explicit destructor behaviour (like class B), is everything ok? I ask this because I wanted to create a class to extend std::string, (which I know is not recommended, but for the sake of the discussion just bear with it), and overload the +=,+ operator. -Weffc++ gives me a warning because std::string has a non virtual destructor, but does it matter if the sub-class has no members and does not need to do anything in its destructor? -- FYI the += overload was to do proper file path formatting, so the path class could be used like class path : public std::string { //... overload, +=, + //... add last_path_component, remove_path_component, ext, etc... }; path foo = "/some/file/path"; foo = foo + "filename.txt"; //and so on... I just wanted to make sure someone doing this path* foo = new path(); std::string* bar = foo; delete bar; would not cause any problems with memory allocation

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  • How to use a Base ViewModel in Asp.net MVC 2

    - by Picflight
    As I familiarize myself with Asp.Net MVC, I am using MVC 2, I have noticed the use of a BaseViewData class in the Kigg project which I am unsure how to implement. I want each of my ViewModels to have certain values available. Using an iterface comes to mind but I am wondering what the best practice is and how does Kigg do it? Kigg public abstract class BaseViewData { public string SiteTitle { get; set; } // ...other properties } public class UserListViewData : BaseViewData { public string Title { get; set; } // .. other stuff } In my WebForms application I use a BasePage that inherits from System.Web.UI.Page. So, in my MVC project, I have this: public abstract class BaseViewModel { public int SiteId { get; set; } } public class UserViewModel : BaseViewModel { // Some arbitrary ViewModel } Referencing the Kigg methodology, how do I make sure that each of my ViewModel that inherits from the BaseViewModel have the SiteId property? What is the best practice, samples or patterns I should be using?

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  • Interoperability when returning derived class by base class in WCF

    - by mt_serg
    I have some simple code: [DataContract] [KnownType(typeof(SpecialEvent))] public class Event { //data } [DataContract] public class SpecialEvent : Event { //data } [ServiceContract] public interface IService { [OperationContract] List<Event> GetEvents(); } [ServiceBehavior] public class Service : IService { public List<Event> GetEvents() { List<Event> events = new List<Event>(); events.Add(new Event()); events.Add(new SpecialEvent()); return events; } } I know that it works fine in case wcf to wcf. but what about interoperability? is it generate standart wsdl and any client can use the service or no?

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  • polymorphism pass instantiated base to deriver

    - by Eric
    I was wondering how to do this, consider the following classes public class Fruit { public string Name { get; set; } public Color Color { get; set; } } public class Apple : Fruit { public Apple() { } } How can I instantiate a new fruit but upcast to Apple, is there a way to instantiate a bunch of Fruit and make them apples with the name & color set. Do I need to manually deep copy? Of course this fails Fruit a = new Fruit(); a.Name = "FirstApple"; a.Color = Color.Red; Apple wa = a as Apple; System.Diagnostics.Debug.Print("Apple name: " + wa.Name); Do I need to pass in a Fruit to the AppleCTor and manually set the name and color( or 1-n properties) Is there an better design to do this?

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  • Encrypt a file base upon a pregenerated "key" C#

    - by Anubis
    Hello everyone. I'm trying to determine the best course of action to implement a simple "licensing" system with a partner of mine. The concept is: Generate an encrypted value based upon several internal hardware components. Have the customer send this value to us which we will implement into our key generator. Once we have that, we add any other restrictions on the license (user, expires, etc.). From there we generate a file which we send to the customer they can add to their installation and voila, happy people about. I have the first part all done. My next part is trying to figure out which encryption methodology I would need to use. I already know Symmetric Encryption is pretty much the only route I can take. Most of the information I have found involves .NET already creating a key from its own internal methods. That's a bit of background, my question is: "Which encryption method could I use which would allow me to encrypt the restrictions based upon the "id" I was given from the customer's computer?" I'm writing this in C# by the way. Any ideas would be greatly appreciated! Take Care!

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  • Abstract base class puzzle

    - by 0x80
    In my class design I ran into the following problem: class MyData { int foo; }; class AbstraktA { public: virtual void A() = 0; }; class AbstraktB : public AbstraktA { public: virtual void B() = 0; }; template<class T> class ImplA : public AbstraktA { public: void A(){ cout << "ImplA A()"; } }; class ImplB : public ImplA<MyData>, public AbstraktB { public: void B(){ cout << "ImplB B()"; } }; void TestAbstrakt() { AbstraktB *b = (AbstraktB *) new ImplB; b->A(); b->B(); }; The problem with the code above is that the compiler will complain that AbstraktA::A() is not defined. Interface A is shared by multiple objects. But the implementation of A is dependent on the template argument. Interface B is the seen by the outside world, and needs to be abstrakt. The reason I would like this is that it would allow me to define object C like this: Define the interface C inheriting from abstrakt A. Define the implementation of C using a different datatype for template A. I hope I'm clear. Is there any way to do this, or do I need to rethink my design?

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  • Dynamically creating objects at runtime that inherit from a base class

    - by Homeliss
    I am writing a game editor, and have a lot of different "tool" objects. They all inherit from BTool and have the same constructor. I would like to dynamically populate a toolbox at runtime with buttons that correspond to these tools, and when clicked have them create an instance of that tool and set it as the current tool. Is this possible, and if so will it be better/easier than creating those buttons by hand?

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  • Call the method of base Class which was over ridden

    - by Abhijith Venkata
    I have illustrated my question in this example class Car { public void start(){ System.out.println("Car Started!!!"); } } class Mercedes extends Car { public void start(){ System.out.println("Mercedes Started!!!"); } } Now, in my main program, I write Mercedes m = new Mercedes(); m.start(); It prints: Mercedes Started!!! How do I call the start() method of Car class using the same object so that the output can be Car Started!!!. Edit: Actually It was asked in an interview I attended. I gave the super keyword answer. But the interviewer denied it. He said he'd give me a hint and said Virtual Function. I have no idea how to use that hint.

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  • Inheritance in Ruby on Rails: setting the base class type

    - by Régis B.
    I am implementing a single table inheritance inside Rails. Here is the corresponding migration: class CreateA < ActiveRecord::Migration def self.up create_table :a do |t| t.string :type end end Class B inherits from A: class B < A end Now, it's easy to get all instances of class B: B.find(:all) or A.find_all_by_type("B") But how do I find all instances of class A (those that are not of type B)? Is this bad organization? I tried this: A.find_all_by_type("A") But instances of class A have a nil type. I could do A.find_all_by_type(nil) but this doesn't feel right, somehow. In particular, it would stop working if I decided to make A inherit from another class. Would it be more appropriate to define a default value for :type in the migration? Something like: t.string :type, :default => "A" Am I doing something wrong here?

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  • Loading an NSArray on iPhone from a dynamic data base url in PHP or ASP

    - by Brad
    I have a database online that I would like to be able to load into an NSArray in my app. I can use arrayWithContentsOfURL with a static file, but I really need to go to a url that generates a plist file from the database and loading it into the array. I can use ASP or PHP. I tried setting the response type to "text/xml", but that doesn't help. Any thoughts?

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  • jQuery arange li order base on #ID

    - by Mircea
    Hi, I have the following code: <ul> <li id="project_25">Proj Something</li> <li id="project_26">Proj Blah</li> <li id="project_27">Proj Else</li> <li id="project_31">Proj More</li> ... </ul> Is there a way to arrange these LIs, reverse their order, based on the LI ID? Something like: <ul> <li id="project_31">Proj More</li> <li id="project_27">Proj Else</li> <li id="project_26">Proj Blah</li> <li id="project_25">Proj Something</li> ... </ul> Thank you.

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  • How to stop Zend Framework from appending '/scripts/' to the View Base Path

    - by Hannes
    Thats basically my code (simplified): class IndexController extends Zend_Controller_Action { public function indexAction(){ $this->view->setBasePath(APPLICATION_PATH . '/views/partner/xyz/'); $this->view->render('node.phtml'); } } Now what I (obvoiusly) want is to use the view script APPLICATION_PATH . '/views/partner/xyz/node.phtml' but ZF always tries to load APPLICATION_PATH . '/views/partner/xyz/scripts/node.phtml' is there any Way around that Behviour?

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  • Multi-tier applications using L2S, WCF and Base Class

    - by Gena Verdel
    Hi all. One day I decided to build this nice multi-tier application using L2S and WCF. The simplified model is : DataBase-L2S-Wrapper(DTO)-Client Application. The communication between Client and Database is achieved by using Data Transfer Objects which contain entity objects as their properties. abstract public class BaseObject { public virtual IccSystem.iccObjectTypes ObjectICC_Type { get { return IccSystem.iccObjectTypes.unknownType; } } [global::System.Data.Linq.Mapping.ColumnAttribute(Storage = "_ID", AutoSync = AutoSync.OnInsert, DbType = "BigInt NOT NULL IDENTITY", IsPrimaryKey = true, IsDbGenerated = true)] [global::System.Runtime.Serialization.DataMemberAttribute(Order = 1)] public virtual long ID { //get; //set; get { return _ID; } set { _ID = value; } } } [DataContract] public class BaseObjectWrapper<T> where T : BaseObject { #region Fields private T _DBObject; #endregion #region Properties [DataMember] public T Entity { get { return _DBObject; } set { _DBObject = value; } } #endregion } Pretty simple, isn't it?. Here's the catch. Each one of the mapped classes contains ID property itself so I decided to override it like this [global::System.Data.Linq.Mapping.TableAttribute(Name="dbo.Divisions")] [global::System.Runtime.Serialization.DataContractAttribute()] public partial class Division : INotifyPropertyChanging, INotifyPropertyChanged { [global::System.Data.Linq.Mapping.ColumnAttribute(Storage="_ID", AutoSync=AutoSync.OnInsert, DbType="BigInt NOT NULL IDENTITY", IsPrimaryKey=true, IsDbGenerated=true)] [global::System.Runtime.Serialization.DataMemberAttribute(Order=1)] public override long ID { get { return this._ID; } set { if ((this._ID != value)) { this.OnIDChanging(value); this.SendPropertyChanging(); this._ID = value; this.SendPropertyChanged("ID"); this.OnIDChanged(); } } } } Wrapper for division is pretty straightforward as well: public class DivisionWrapper : BaseObjectWrapper<Division> { } It worked pretty well as long as I kept ID values at mapped class and its BaseObject class the same(that's not very good approach, I know, but still) but then this happened: private CentralDC _dc; public bool UpdateDivision(ref DivisionWrapper division) { DivisionWrapper tempWrapper = division; if (division.Entity == null) { return false; } try { Table<Division> table = _dc.Divisions; var q = table.Where(o => o.ID == tempWrapper.Entity.ID); if (q.Count() == 0) { division.Entity._errorMessage = "Unable to locate entity with id " + division.Entity.ID.ToString(); return false; } var realEntity = q.First(); realEntity = division.Entity; _dc.SubmitChanges(); return true; } catch (Exception ex) { division.Entity._errorMessage = ex.Message; return false; } } When trying to enumerate over the in-memory query the following exception occurred: Class member BaseObject.ID is unmapped. Although I'm stating the type and overriding the ID property L2S fails to work. Any suggestions?

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  • Base class with abstract subclasses in C# ?

    - by Nick Brooks
    public abstract class Request { public class Parameters { //Threre are no members here //But there should be in inherited classes } public Request() { parameters = new Parameters(); } public Parameters parameters; } Two questions: How do I make it so I can add stuff to the constructor but the original constructor will still be executed? How do I make it so the subclasses can add members to the Parameters class?

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