C++ :: Have 1 Static Variable With Instance Different Value
Sep 11, 2014can i have 1 static variable with instance different value?
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C++ :: Difference Between Static Local Variable And Static Global Variable?
Aug 5, 2013Here is the code,
Code:
class A {
};
A& CreateObject() {
static A a;
return a;
} static A aa;
int main() {
return 0;
}
So is there any difference between a defined in CreateObject and aa?
C# :: Static And Delegate - Cannot Be Accessed With Instance Reference
Feb 25, 2014I'm getting some errors while i try to make a program code in C#Net. Here is the part of code that are returning error and a printscreen...
public static void Func_Register(string function, Del func) {
funcs.Add(function, func);
return;
}
Image 1: [URL] ....
private void console_Load(object sender, EventArgs e) {
CAPI.SetRTB(cmd_text);
CAPI.Func_Register("Console.Test", test);
CAPI.Func_Register("APP.Exit", Application.Exit);
[Code] .....
Image 2: [URL] ....
The idea of the code is to make a console to parse some commands. And have some commands with arguments and others no. Without the static the program return other error that is...
Image 3: [URL] ....
C :: Static Variable Usage
Dec 27, 2013I was exploring static variable by writing code snippets. I tried below code and it ended up throwing error saying "error: storage class specified for parameter 'b'"
Why static cannot be used in func() ?
Code:
int main() {
int a;
a=5;
func(a);
printf("%d",a);
return 0; }
void func(static int b)
{b=6;
printf("%d",b); }
C++ :: Static Variable Declaration
Oct 4, 2014If i declare 2 variables like this static int first, second; will both of them be declared static or will only first be declared static and second a regular variable?
View 5 Replies View RelatedC++ :: Static Variable In Member Function
Aug 27, 2014I need to keep a static variable in a member function of a class that I have many objects of. I've had some trouble with it, and when I read up I found that such variables are static across all instances. Is there any way around this?
View 3 Replies View RelatedC++ :: Static Variable To Time Struct
Jan 21, 2013In a function, I have a static variable that I want to assign the time in seconds when a certain condition is met and keep that value until a different condition is met. The time value is a struct. Since now->sec is always incrementing, will timeWhenEventMadeActive below hold onto the initial value or will it increment every time the function is called? I cant seem to test this.
static time_t timeWhenEventMadeActive = 0;
static bool initTime = 0;
if (!initTime) {
timeWhenEventMadeActive = now->sec; //holds uptime value in seconds
[Code] .....
C++ :: Static Constant Member Variable
Jun 6, 2013What is the problem with the following code is? It compiles with Visual C++ 2012 but does not with g++:
//a.h
#ifndef Loaded
#define Loaded
using namespace std;
class MyClass{
public:
static const int MyStaticValue = 200;
[Code] ....
If I try to compile this using the command
g++ a.cpp b.cpp
I get an "undefined reference to 'MyClass::MyStaticValue'" error for the line "A = MyClass::MyStaticValue;" in main(). The strange thing is that if I change the line to "A = (int) MyClass::MyStaticValue;" it works fine and the output is
200
200
as expected.
The code also compiles under g++ if I move the defintion of MyStaticValue from a.h to a.cpp by const int MyClass::MyStaticValue = 200;
C++ :: How To Reference Static Variable In Another File
Apr 15, 2014I've got a static variable in the master file called :
static dtNavMesh *g_navMesh;
I just need one copy of this object.
In another module, I need to reference this global variable.
extern dtNavMesh *g_navMesh;
C++ :: Static Variable And Function With Template
Jul 18, 2012I try to create small project in order to better understand how key word static works with templates . However some compiles errors crush my plan.
1>------ Build started: Project: 4.2b - Ex 1. Static Variable for Array Def Size. Templates, Configuration: Release Win32 ------
1> main.cpp
1>c:all myс++ha level 6solution level 6solution level 64.2b - ex1. static variable for array def size. templatesarray.cpp(40): error C2724: 'Array<Type>:efaultSize' : 'static' should not be used on member functions defined at file scope
[Code] .....
C++ :: Static Array Variable Size Allowed?
Mar 1, 2013I have a function like this
void foo( int i) {
...
uint8_t buf[ i];
...
}
And I don't understand why the compiler is not complaining... I'm using g++ -c -g -Wall to compile ....
C++ :: Static Variable Inside A Member Function
Jul 20, 2013Say you had:
class Foo{
public:
//...
void funky();
[Code] .....
Would each instance of Foo create a new counter variable, or would it remain the same for all of them, i.e. baz.funky() would always use the same counter variable? What if the class was a template?
C++ :: Static Variable Initialization - Console Output Of Program
Oct 11, 2013What does the order of console output from your program tell you about when the static object is initialized?
#include <iostream>
using namespace std;
//class
class Firstclass {
private:
Firstclass(); //constructor
~Firstclass(); //destructor
[Code] ....
Doesn't it allocate the class static variable to the heap, thus executing its algorithm then destroying it when the program ends - or. What exactly does it tell me? When the static variable is initialized, it takes place first before any of my other functions?
C++ :: Initializing Static Map Of Variable Type Abstract Class?
Dec 3, 2014A have two classes, one inheriting the other, and the parent class being abstract (I plan on adding more child classes in the future). For reasons I won't bother mentioning, I'm making use of an STL container as a way for me to access all of the child objects in the heap. I've done so by making use of a map, with key type int and value type being a pointer to the parent class:
//PARENT.H
class Parent {
protected:
static int n;
static std::map<int, Parent*> map;
public:
virtual void pureVirtual() = 0;
[code]....
The Problem:In line 5 of Parent.cpp, initializing the value of the element to new Child won't work, as according to the compiler, the Child class hasn't been declared yet, and including Child.h into the Parent.h only opens an even bigger can of worms.I also can't initialize it as new Parent, seeing as the parent class is an abstract one.
The Question:Is there a way I can initialize the static map properly. Making the Parent class abstract is not an option.
C/C++ :: Difference Between Declaring Static Variable Inside And Outside Of Main
Apr 6, 2012I want to know
prog1.c
#include<stdio.c>
static int c=6;
int main() {
/*code*/
}
prog2.c
#include<stdio.h>
int main(){
static int c=10;
}
what would be the difference between these two program in the fuctioning of static keyword ?
Visual C++ :: Hash Table - How To Setup Static Variable
Apr 22, 2014I am having trouble getting the cout statements that I commented out to work properly. And I can't figure out why the first movie in the movies.txt file displays at the end of the list in my output screen when it should only display once as the first item. I am also having trouble figuring out where and how to set up the static variable.
Purpose : This assignment requires that you to develop a program using the classes listed above. Specifically you will build a hash table containing movie data. The collision strategy will be to build linked lists as the array elements.
Program Specifications : Your program will read the data from the file named Movies.txt located in the StudentFiles1.zip file on the Connections Portal. Each record contains 2 fields separated by a space. They are:
FieldsData Type
Motion Picture Association Code (MPAC)Integer
Movie NameString
Your application program will read each record, create a Movie structure instance and place that structure instance into the hash table.
You will need to modify the appropriate code to provide for an audit trail of the hash table construction. To accomplish this, you will use cout statements in the above class member functions. You will need to modify them to include couts, but the modifications will be relatively small. If not, you are doing it wrong. The hashing algorithm to use is:
Index = int ( 0.618033 * MPAC) % size
Make the array size a constant and set it to 10.
Include a counter for the number of collisions that occurred in building the hash table. Including a static variable in the LinkedList or List class is the best method for doing that.
See the sample audit trail below for the first 5 records on Movies.txt and the size of the hash table set to 3. This is shown for illustration only. The full file will have different locations calculated.
1101-Casablanca is being added
The hashed location is 2
There was no collision loading 1101-Casablanca
------------------------------------------------
1200-Duck Soup is being added
The hashed location is 0
There was no collision loading 1200-Duck Soup
------------------------------------------------
[Code] ....
After the above is displayed, prompt the user to enter the MPAC of a movie to locate. Produce an audit trail when locating the requested movie as shown below: Make sure you list all movies that have collided at the hashed location. That may also cause you to modify one of the existing ADTs a little.
Will search for 6601
at the hashed location is 2
There was a collision here with 6601-Wizard of Oz
There was a collision here with 1101-Casablanca
retrieved from hash table: 6601-Wizard of Oz
[Code] ....
C++ :: Storing Static Class Members Of Dynamic Variable Type In DLL
Oct 15, 2013How I can implement it.
Tickable.h
#include <list>
#ifdef TICKABLE_EXPORTS //Automatically defined by MSVS
#define DLL __declspec(dllexport)
#else
#define DLL __declspec(dllimport)
#pragma comment(lib, "Tickable.lib")
#endif
class DLL Tickable{
[Code] ....
error LNK2001:
unresolved external symbol "private: static class std::list<class Tickable*,SKIPPED BITS> Tickable::subs" HUGE_SYMBOL_LIST
PATHTickable.obj
I know with such a tiny and insignificant class the dll export seems pointless but this class is actually intended to be a .lib ONLY. But it is derived from by .dll style classes, and through inheritance this error is the exact same as what appears in the derived class, I just imagine that the cut down version would be easier to work with.
Is it possible to hold either a static variable in a dll which is of a dynamic type, OR would it be possible to reference an external variable which is static throughout the instances and this variable can be chucked away in a namespace of mine somewhere?
I suppose my only other option (if this is possible) would be to define a maximum instance number and create a standard array of pointers but this could both waste so much memory when not in use and cause problems if I need more memory.
C++ :: Undefined Reference Error When Accessing Static Variable Inside Member Function
Feb 10, 2013I am modifying a set of static variables inside of the class's member function. The static variables are private. An example of what I'm doing is as below,
utilities.h
-----------
class utilities {
private:
static int num_nodes;
public:
void parse_details(char* );
[Code] ....
I get a compilation error in the function void utilities::parse_details(char* filename)
which says: undefined reference to `utilities::num_nodes'
compiler: g++
C++ :: Do Static Functions Have Access To Non Static Data Members Of A Class
Apr 17, 2013From my book:
"A static function might have this prototype:
static void Afunction(int n);
A static function can be called in relation to a particular object by a statement such as the following:
aBox.Afunction(10);
The function has no access to the non-static members of aBox. The same function could also be called without reference to an object. In this case, the statement would be:
CBox::Afunction(10);
where CBox is the class name. Using the class name and the scope resolution operator tells the compiler to which class Afunction() belongs."
Why exactly cant Afunction access non-static members?
C++ :: Accessing Non-static Members Inside Static Member Functions
Sep 11, 2013What are the workarounds for accessing the non-static member variables of some class(Say A) inside static member functions of another class(Say B)? I am coding in c++. Class A is derived with public properties of class B. Any pointers?
View 7 Replies View RelatedC# :: Static Method Inside Non-static Class
Aug 22, 2014Have following code:
class Program
{
static void Main(string[] args)
{
[Code]....
My question according to what i just wrote:
1. Is that mean that Do() is only available for use by Dog itself because Dog is 'oryginal' Dog, and if i create new dogs - instances of oryginal Dog (dog1, dog2 ...) they cant access because Do is only available fo 'oryginal' one? Is that correct thinking?
2. If i would want to have something common (e.g value) for all dogs is that good way to create static field/method for Dog instead of non-static once then all instances of Dog would access Dog static member to get/change it? Just stupid example: static method GetAmountOfLegs() which return 4 Then all instances can take/call that value from Dog. Is that correct thinking?
C++ :: Getting Singleton Instance
Oct 25, 2014Code:
class BoundingBoxTest : public DemoApplication {
public:
#ifdef DYNAMIC_CHARACTER_CONTROLLER
btCharacterControllerInterface* m_character;
[Code] ....
I am creating the object by calling : BoundingBoxTest::Create();
Do I make a getter to retrieve the demo object or do I build on the Create() method... So that it will return the instance if it is not null. and creates one if there is none?
C++ :: Why Would A Class Allocate An Instance Of Itself
Oct 4, 2014I'm currently learning the Qt framework and doing my first tutorial. Straight away I saw something that baffled me:
notepad.h
Code: namespace Ui {
class Notepad;
}
class Notepad : public QMainWindow
[Code] ....
Note the ui pointer and the heap allocation in the class constructor; I can't wrap my head around why one would do this. What's going on here?
C++ :: Declaring New Instance Of A Class
Nov 6, 2014I am putting a instance o the Vehicle Class inside the constructor of the Calculate Class then calling it later. I get a warning saying the variable is not used and a error when I try to used the functions from the vehicle class saying use of undeclared identifier.
Code:
#include <iostream>
#include "Calculate.h"
#include "Vehicle.h"
#include <fstream>
Calculate::Calculate(){
[Code] ....
C++ :: Vector Is Different For Every Class Instance
Feb 12, 2014Okay so I have a class Student, which takes a number and a vector as a parameter for the constructor. Everything works well, until I output the values of the vector for every instance. The problem is that the same vector is being shared with EVERY instance I create, but I want it to be unique for every single one!
//Student.h
#ifndef __Grade_calculator__Student__
#define __Grade_calculator__Student__
#include <iostream>
[Code].....
C++ :: How To Have A Class Return Instance Of Itself
Nov 24, 2012I was wondering if (in C++) you can instantiate a class (class foo) then have said class return the already instantiated object. (foo::instance())
In other words, can I have a class return it's-self via it's own methods? I want to be able to create a class (i.e. class foo) early in my program so it is already setup and ready to go. Then, farther down the line, I want to be able to call functions from that class without having to pass that object as an argument to my calling function. Can I do something like so:
MyClass::ReturnSelf()->foo();
or
MyClass::ReturnSelf().foo();