char to listbox

[Watcher]

Hi I haven´t found a satisfying answer for question how to include char to listbox and back line from listbox to char. Thanks for answers.

[JP]

This may work:

char* cStr = "something";
wchar_t wStr[255];
swprintf(wStr, 255, L"%s", cStr);
listBox->addItem(wStr);

The following will probably not work
char cStr[255];
sprintf(cStr, "%s", listBox->getListItem(0));

*Edited due to Vitek's comments*

[Watcher]

I´m afraid it doesn´t work

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invalid conversion from `int' to `const wchar_t*' 
initializing argument 2 of `int swprintf(wchar_t*, const wchar_t*, ...)' 

[Watcher]

And when I tried this, it converts only the last word of the char. For exampe if char is abcd, in lisbox is shown only d.

swprintf(wStr,L"%c", chattext);

[JP]

Strange, compiles fine for me (dev-c++)

[Watcher]

Could you send me please what header files do you have included and what is their sequence? I moved with irrlicht.h and suddenly your code works, but i still got only the last letter of my char.
swprintf(wStr,255,L"%c", chattext);

[JP]

I didn't have any special header files included, it's just a standard C function.

[vitek]

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wchar_t wStr[255]; 
swprintf(wStr, 255, L"%s", myChar); 
listBox->addItem(wStr); 

char cStr[255]; 
sprintf(cStr, "%s", listBox->getListItem(0));

Both of these are dangerous and incorrect.

In the first one, you are passing a character [I'm assuming it is at least a wide character] where the runtime system is expecting an array or pointer. When the system reads the myChar parameter, it gets the character value and then treats it like a pointer to a string. At the very least I would expect that to crash.

In the second one, you are converting a wide character string to narrow string. Usually this requires some sort of special format string to indicate that the source is a wide string. Microsoft uses "%S", but other systems may do it differently.

[vitek]

Watcher,

What is chattext? Is it a char, wchar_t, char* or wchar_t*? I ask because it is not really clear what you are doing. Some of your comments seem to indicate it is a string of some sort, but others indicate it is just a character.

[Watcher]

It is just character

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char chattext;

And you were right it crashed. I had to use %c but it wrote to listbox only the last letter of my character.

I have char chattext = 'hello' and it wrote only o.

[JP]

"hello" is not a char, it's a char*; an array of chars basically. That's probably why it's only showing the last character. Change it to char* and it may work.

Vitek: by myChar i meant a char*, though it's not named very well And the latter one, converting wchar_t* to char* was just a guess really off the top of my head! I've edited my original post to improve it somewhat

[vitek]

It is just character

And you were right it crashed. I had to use %c but it wrote to listbox only the last letter of my character.

I have char chattext = 'hello' and it wrote only o.

The problem appears to be your understanding of characters and character strings. If you write this:

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  char chattext = 'hello';

you should get a compile error, or at the very least a warning. The text 'hello' is composed of 5 characters and you're trying to stuff that into the space for just one character.

If chattext is more than one character, it is a character string, array of characters, or more simply a string. You would write this

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  char* chattext = "hello";

Now chattext would be all 5 characters 'h', 'e', 'l', 'l', and 'o'.

Now back to your original problem... I think you are trying to make a listbox display a text string, and retrieve that string back from the list box. There is a silent issue at work here, and that is the conversion from wide to narrow characters and character strings. You can usually avoid the issue entirely by always using wide characters/strings. If you are always using wide strings then the answer is trivial...

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// add an item with the text "hello"
wchar_t* chattext = L"hello";
listBox->addItem(chattext);

// get the item text back as a wide string
wchar_t* itemtext = listBox->getListItem(0);

You could also use the wide string class provided by Irrlicht.

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// add an item with the text "hello"
core::stringw chattext(L"hello");
listBox->addItem(chattext.c_str());

// get the item text back as a wide string
core::stringw itemtext = listBox->getListItem(0);

If you must, for some reason, convert the from narrow to wide strings, then there are two ways. Irrlicht provides a mechanism to do this via the string conversion constructor.

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core::stringc chattextA("hello");
core::stringw chattextW(chattextA.c_str());

I don't believe that the conversion that is done here is correct, but it will probably work fine provided you are using the lower 128 ASCII characters.

There are the functions wcstombs and mbstowcs for doing the conversion correctly using locale information.