irrlicht's string class template [Solved]

[JuicyLobster]

Im new to c++, I usually use C# and java.

What I am trying to do is place mouse x and y position values on the screen. The problem is in c/c++ u cant add strings togeather, and for the font draw function it requires a wide character.

Heres what I tried:

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		string* mxy;
		mxy->append(input->mouseX());
		mxy->append(", ");
		mxy->append(input->mouseY());
		fWhite->draw(mxy->c_str(),rect<s32>(50,100,0,0),SColor(255,255,0,0));

After I tried to compile I realized its a template class and that im probably using append() wrong too because it has no overloads for what im trying to do, but its just an example to let you know what im trying to do here.

Can someone point me in the right direction or toss me an example of how to use irrlichts string class? I'm hoping it will be shorter than using itoa, stringf etc...

edit: to make it clear im trying to concatonate the x and y values seporated by a comma, and convert using .c_str() to wchar_t

[scgtrp]

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string<wchar_t> s;
s += 123;
s += L", ";
s += 456;
std::wcout << s.c_str() << std::endl;

Note that you don't need to use a pointer, and if you did you'd want to initialize it to something (how did yours not crash?)

[JuicyLobster]

oh so thats how you use templates? Makes sense to me now, thanks

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		string<wchar_t> mxy;
		mxy = input->mouseX() + L", " + input->mouseY();
		fWhite->draw(mxy.c_str(),rect<s32>(50,100,0,0),SColor(255,255,0,0));

btw, it didnt crash because it did not compile, I only said I tried to compile . It didnt compile because I didnt pass it a type to use with the template.

---

Alright its crashing because i need to cast the mousex into wchar_t somehow, i think

tried this too but it still crashes :/

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		string<wchar_t> mxy;
		mxy = string<wchar_t>(input->mouseX());
		mxy += L", ";
		mxy += string<wchar_t>(input->mouseY());
		fWhite->draw(mxy.c_str(),rect<s32>(50,100,0,0),SColor(255,255,0,0));

[scgtrp]

The += operator converts it for you. = is assuming you meant 123 as in whatever ASCII character 123 corresponds to ({?). You could, however, do

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string<wchar_t> s;
s += 123 + L", " + 456;

[JuicyLobster]

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		string<wchar_t> mxy;
		mxy += 123 + L", " + 456;
		fWhite->draw(mxy.c_str(),rect<s32>(50,100,0,0),SColor(255,255,0,0));

Tried that instead of using the functions to return mouse position (think that was crashing it). However the text draw function is not drawing any of the string values.

[scgtrp]

Try this:

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fWhite->draw(mxy.c_str(), rect<s32>(50, 100, 150, 130), SColor(255, 255, 0, 0));

[JuicyLobster]

still not showing. I've always used the last 2 arguments as 0 because it seemed they werent being used. If I substitute the mxy.c_str() with L"Test123" it shows. Something wrong with the string somewhere

edit: could it be that using += 123 + L", " + 456 is just adding up the characters as a single char value which then my font has nothing to show it as?

This willdisplay the character a:

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		string<wchar_t> mxy;
		//mxy += 123 + L", " + 456;
		mxy = L"a";
		fWhite->draw(mxy.c_str(),rect<s32>(50,100,0,0),SColor(255,255,0,0));

so will:

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		string<wchar_t> mxy;
		//mxy += 123 + L", " + 456;
		mxy += L"a";
		fWhite->draw(mxy.c_str(),rect<s32>(50,100,0,0),SColor(255,255,0,0));

[scgtrp]

Strange. I didn't test what I posted, just took a look at the API docs - I read it as the rectangle actually being used as a rectangle and not a point, i.e. the text would be clipped to fit inside that rectangle.

Try using += 3 times to test your theory. It could be true.

[JuicyLobster]

yup it seems to be the case (finally )

Can only assign one array of chars per += operator. Else it will change the value of the text being concatonated;

[scgtrp]

Yes, it seems you're right. I did come up with this funky syntax which works, but looks horrible unless you're entering the IOCCC:

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(((mxy += 123) += L", ") += 456);

[JuicyLobster]

yup, thanks again, solved.

[FuzzYspo0N]

something more irr friendly :


core::stringw mxy;

So try :

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mxy = core::stringw(core::stringw(123).append(", ")).append(456);

Or

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mxy = core::stringw(123) + core::stringw(", ") + core::stringw(456);

These arent tested, but should be fine