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Calculator Community => Other Calc-Related Projects and Ideas => TI-Nspire => Topic started by: CiriousJoker on February 08, 2015, 07:36:15 pm

Title: Cant return code in a static function (just read it, it's rly hard to explain)
Post by: CiriousJoker on February 08, 2015, 07:36:15 pm

Sorry to bug you guys again, but i really cant figure out why this doesnt work :(

Here's the important code snipped im talking about:

Code: [Select]

class Level
{
public:
static bool InitLevel();

private:
static string LevelDataString;
};

bool Level::InitLevel()
{
if(( (Level::LevelDataString).size() % 6) != 0)
{
return false; // This line crashes it all
}
return true;
}


This crashes:

Code: [Select]

if(( (Level::LevelDataString).size() % 6) != 0)
{
char popup_result[256];
show_msgbox("Error", "The level seems to be broken.");
}
return true;


This also crashes:

Code: [Select]

if(( (Level::LevelDataString).size() % 6) != 0)
{
return false;
}
return true;


This works (but makes no sense, i just tested if ANY code makes it crash):

Code: [Select]

if(( (Level::LevelDataString).size() % 6) != 0)
{
int test = 1;
}
return true;

I seriously dont get why i cant just return false from a boolean function ...
I mean, does it crash in "normal" for pcs too or is this just an ndless problem?

Title: Re: Cant return code in a static function (just read it, it's rly hard to explain)
Post by: bb010g on February 08, 2015, 11:44:48 pm

Do you ever initialize LevelDataString? E.g.

Code: [Select]

std::string Level::LevelDataString = "PotatoLand";


Title: Re: Cant return code in a static function (just read it, it's rly hard to explain)
Post by: Vogtinator on February 09, 2015, 11:32:28 am

AFAIK "static std::string LevelDataString" in the class definition isn't enough. It's only in a header file, but it doesn't have a place to stay, in your current code, it does not exist.
You have to put "std::string Level::LevelDataString" somewhere in a .cpp file. It could also be because you're using a too old version of the SDK, without support for C++ as it was first added by tangrs somewhere around r865.

Title: Re: Cant return code in a static function (just read it, it's rly hard to explain)
Post by: CiriousJoker on February 09, 2015, 12:22:40 pm

i've added this above the definition of the function:

Code: [Select]

string Level::LevelDataString = "002:000:001+000:001:001+001:002:003";

But it seems to be a problem with the if testing, because if i just write:

if(true)
{
    return false;
}

it works

Title: Re: Cant return code in a static function (just read it, it's rly hard to explain)
Post by: ajorians on February 09, 2015, 07:02:57 pm

Hi Virusscript24,

Vogtinator is correct.  Having a static class member variable also needs something else.  Here is a small example:

Code: [Select]

#include <iostream>
class Something
{
public:
    static int s_nValue;
};
 
int Something::s_nValue = 1;//This part here is needed
 
int main()
{
    Something cFirst;
    cFirst.s_nValue = 2;
 
    Something cSecond;
    std::cout << cSecond.s_nValue;
 
    return 0;
}

See this tutorial here: http://www.learncpp.com/cpp-tutorial/811-static-member-variables/

Hope that helps!