C++ :: Implementing Static Templated Method In Cpp File
Apr 16, 2012
I declared a member method to a class in its header file and implemented it in the cpp file. When I build and run the project in XCode, everything works fine. When I try to do it with a makefile, I get undefined symbols linker errors.
I'm pretty sure that there is a weird namespace gotcha that I'm unaware of that LLVM (default OSX compiler) is compensating for that g++ isn't. Or maybe something weird with the optimization? I want the tests running at that level to make sure everything that is volatile is declared as such.
I would like to define a templated class while implementing default value on templated arguments. I don't know how to do that with string templated variables.
For exemple:
Code: template <class T> class A { public: A() { version = ???? } std::string_base<T> version; };
I don't want to pass the default value as parameter of the constructor. how I can do this?
I've been trying for more than one month to access a method found in a library called libcocosnas_static.a. I'm using Cocos2d-X version 2.0.4. The library has been used many times by my company to make games using cocos2d-1.0.1-x-0.12.0 without any problem.
This is what I've done: 1- I added the include paths of the library to both eclipse and Android.mk 2- Included the .h file using #include "NASPlatformUtil.h" 3- Added the libcocosnas_static.a file to the proj.androidobjlocalarmeabi folder 4- Added "LOCAL_WHOLE_STATIC_LIBRARIES += cocosnas_static" to the Android.mk file 5- Called the function using: NASPlatformUtil:: openUrl("http://xxx.xxx.com/");
I can right click on the function, click Open Declaration and get it without any problem, but the compiler keeps on giving me that dreaded error...
This problem just seems really strange to me because it is simple yet for some reason my class cannot pass into another class. The class PASS_OBJECT has a static array (even with 1 element this doesn't work) and when I try to pass this class (after it is initialized) I seem to lose the data inside the PASS_OBJECT. Not only that but even when I declared the class OBJECT with the type of PASS_OBJECT<int> I seem to lose the integer 99. Here's the code, note that if you comment out line 89, 92 and 93 you will notice that line 90 outputs In main 2: 99 just fine but it doesn't otherwise???
#include <iostream> const int size = 1; template <class T> class PASS_OBJECT; template <class S> class OBJECT {
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?
I would like to avoid throwing things in constructors as much as possible.
Is this good design to have a static class method that checks arguments the caller will give to the constructor. The documentation of the class will say, thou shall call this method to validate thine arguments before calling the constructor, or else segfault may befall thoust.
I have function that returns historical data. I can access it, using file name. If I use file name, it reads that file and saves it to dictionary, so that in the future, if historical data is required for the same file, it does not read it again (it's lazy loading). If no file is supplied to the function, it tries to read file which is given in app settings.
However, for unit testing, I do not want to read any file. Instead, I want it to use small sample of hardcoded historical data. In order to do that, I think, I need to introduce interface to it. Then I can use some IoC to choose between different implementation for unit testing purpose and ordinary launch of application.
Function to get history is given as follows:
public static class Auxiliary { private static Dictionary<string, MyData> _myData; public static MyData GetData(string fileName = null) { // ... } }
I have created default Unit Test project with Visual Studio so, as far as I know, by default it uses MSTest as test runner and MSUnit as unit testing framework but it does not have any IoC container so I should manage NuGet packages for solution and install Unity.
As far as I know, MSUnit (aka Moles) can unit test static methods (it's unconstrained isolation framework, like Typemock Isolator, unlike NUnit) but still many people suggest not to use any static methods for unit testing.
Should I use shim or stub [URL] Stubs should be used for faking external dependencies and here it is not external library, but my own code.
I am writing my program on C++ language. I have one promblem. I need to set signal handler for my process. As the signal is related with the process on system level I have faced the problem.
My program consists several classes. They are connected together. But it doesn't metter in this case. The problem is that I need to access to member and methods of the class from my signal handler. For instance , I have class named Foo at it has some members and methods.
So from my handler I need to call its function and change members.
I understand that compiler should know that this class instances will exist during all program execution.
I have tried to set static member class Foo instance in another class , but this didn't solve the problem.
What is correct approach to do this. How to correctly implement signal handling in such case.
Here is example of my code
Code: class MyContainer{ private: std::vector<Foo> container; public: int removeFromContainer(Foo* aFoo) {
How do I call a class method which is defined in a .hxx file separately to a .cpp file? Is it any different from how we normally do it (using the scope resolution operator after the class name and then the method name with parameters) ?
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."
What 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?
I am trying to write a program which involves linked list. i have to create a method called add_aa( str ). I am reading from a text file. in the text file it just contains the values for str. what I am trying to do is create the method add_aa( str ) and add what corresponds to str from the file. here is what the output should look like. and what i have is very basic. here is what i have
If your strings are all well-formed it is possible with the following regular expression:
String[] res = str.split(",(?=([^"]|"[^"]*")*$)");
The expression ensures that a split occurs only at commas which are followed by an even (or zero) number of quotes ... and thus not inside such quotes).
Nevertheless, it may be easier to use a simple non-regex parser.
But the .split gives me an error and .Split doesn't work either.
I have a libcx3d.a which contains my VrmlParser class and other classes which are used by VrmlParser. I have a main.cpp which does this :
VrmlParser vp = new VrmlParser(); double **VOB = vp.getVOB();
When I compile using g++ main.cpp -o main -L. -lcx3d, I get the following errors :
'VrmlParser' was not declared in this scope. expected ';' before vp. 'vp' was not declared in this scope.
There is a header file called "VrmlParser.h" in the static library. Should I include this header file in main.cpp ? If so, will include "VrmlParser.h" work ? I have the .a and .cpp in the same directory. I can't find the header file for the static library.
So I'm rewriting an old project of mine, and I'm trying to determine if there's truly any better way to map the data taken from a text file "dictionary" into the correct class fields for further processing. For example:
In each of these, I'd need the "value" (MY_FIRST_NAME, MY_LAST_NAME, etc) from the "keys" (FNAME, LNAME, etc) to be mapped to the proper class fields. Say, for example, I had this:
Class DataProcessing { public string Address; public string FirstName; public string LastName; public int TotalCalls; ... }
I would need DataProcessing.Address to be set to the value in the ADDR key/value pair. The same would be true for each other field. The problem is that based on the text file's source (which isn't under my control, and won't be changed anytime soon), the key/value pairs are not always in the same place...so a second file could have the data as such:
TOTCALLS=47 ADDR=123 SOMEWHERE LN, NOWHERESVILLE, TX 01234 LNAME=DARKPOETCC'S LAST NAME FNAME=DARKPOETCC'S FIRST NAME
Any smarter way to do this than looping through each line that was read in from the file, and determining where it belongs, such as (pseudo code follows):
IF FieldName == "TOTCALLS" THEN //Assign to TotalCalls field ELSEIF FieldName == "ADDR" THEN //Assign to Address field ELSEIF FieldName == (You get the picture...) //Do thing N_Field
I have a question similar to the one here: [URL] .....
The main difference is I would like to pass a method of derived class as a parameter to some other method in its template base class.
template <typename BaseType> class Base { public: typedef void (Base::*Callback)(int A);
[Code] .....
The above is an example which does not compile. My compiler complains that the two BaseMethod() calls in DerivedMethod() are invalid uses of non-static member function.
Is this not possible to do, or is my syntax simply wrong? All I want is to be able to pass as an an argument to a method in the base class from the derived class some callback as a variable for the base class to invoke later.
template <typename T> struct avl_tree { T data; int balance; struct avl_tree <T> *Link[2]; static int (*comp)(T, T); };
In main, I have a function like so: int compare(int a, int b) { return ( a - b ); }
Now how do I assign the function pointer in my avl_tree class to the compare function?
I did this: int (avl_tree<int>::*comp)(int, int) = compare;
But I got the compiler error: Tree_Test.cc: In function ‘int main()’: Tree_Test.cc:27:42: error: cannot convert ‘int (*)(int, int)’ to ‘int (avl_tree<int>::*)(int, int)’ in initialization
// Predefine template delegate factory template < typename R, typename... Args > class brGenericDelegate ; // C++11 template alias to announce functor definition template < typename R, typename... Args > using brGenericDelegateType = std::function< std::shared_ptr<R>(Args...) > ;
[code]....
This template works fine for me. Now I have to compare, if the functors of the generic templates are equals ore not. Actually I see no way to reach this aim, because I've to cast the brDelegate on each request.
Can I determine if a templated class has a particular constructor, in my case using a string within function to which T is used?
Code:
template<class T> void MakeObject(std::vector<T>& dataVector) { std::string str "con string,Joe,24"; // catch if T has string constructor T someObject(str); // T someObject should have constructor from string dataVector.push_back(someObject); }
