convert 'char *' to 'LPCTSTR'

neha agarwal27

Hi all, I am trying to print size of my file in a list control using this code

int len = finder.GetLength();
char *len_str = new char;
sprintf(len_str,"%d",len);
m_Files.SetItemText(i,1,len_str);

but it gives this error error C2664: 'CListCtrl::SetItemText' : cannot convert parameter 3 from 'char *' to 'LPCTSTR' i am using VC-2005 can anybosy tell me how to resolve this problem

Cedric Moonen

Don't use a char pointer but a TCHAR pointer (which is a macro that resolves to wchar if UNICODE is defined or to char if UNICODE is not defined). And use _stprintf instead of sprintf. You also forgot to create an array of the correct size.

int len = finder.GetLength();
TCHAR *len_str = new TCHAR[len];
_stprintf(len_str,_T("%d"),len);
m_Files.SetItemText(i,1,len_str);

EDIT: don't forget to delete[] the buffer once you are done with it.

Cédric Moonen Software developer
Charting control [v1.2]

Kenan Aksoy

I think you should use swprintf instead of stprintf

dlfkgj lsdfkglfkgjlfgl jldfk fldkk jk

krmed

Since len is apparently the length of a file, you won't need to allocate your buffer that big, but you will need enough characters to hold all the digits.

int len = finder.GetLength();
TCHAR *len_str = new TCHAR[(int)(log10(len) + 2)]; // leave one extra character for null terminator
_stprintf(len_str,_T("%d"),(int)(log10(len) + 2));
m_Files.SetItemText(i,1,len_str);
delete[] len_str;

Hope that helps.

Karl - WK5M PP-ASEL-IA (N43CS) PGP Key: 0xDB02E193 PGP Key Fingerprint: 8F06 5A2E 2735 892B 821C 871A 0411 94EA DB02 E193

Cedric Moonen

No, stprintf is a macro that resolves to sprintf if UNICODE is not declared or to swprintf if UNICODE is declared. So your code still compiles even if you change unicode settings.

Cédric Moonen Software developer
Charting control [v1.2]

Cedric Moonen

Yes that's right, I didn't think too much before posting my reply :-D. But you should print the len in the string, not the number of characters ;P

Cédric Moonen Software developer
Charting control [v1.2]

CPallini

I understand the point, but maybe it would be nice to avoid both continuos allocation/deallocation of memory and use of the log10. Simply allocate once a (relatively) big buffer on the stack.

If the Lord God Almighty had consulted me before embarking upon the Creation, I would have recommended something simpler. -- Alfonso the Wise, 13th Century King of Castile.

David Crow

neha.agarwal27 wrote:

char *len_str = new char; sprintf(len_str,"%d",len);

Since you are using MFC:

CString len_str;
len_str.Format("%d", len);

"Normal is getting dressed in clothes that you buy for work and driving through traffic in a car that you are still paying for, in order to get to the job you need to pay for the clothes and the car and the house you leave vacant all day so you can afford to live in it." - Ellen Goodman

"To have a respect for ourselves guides our morals; to have deference for others governs our manners." - Laurence Sterne

krmed

Well, perhaps that would be ok, but if the file size is large (2 GB) the new of a 2GB char array would probably fail, and you don't need anywhere near that many characters to hold a file size. Perhaps a fixed buffer size of say [MAX_PATH_LEN] (which is 256) would be more than enough characters to hold any file size.

Karl - WK5M PP-ASEL-IA (N43CS) PGP Key: 0xDB02E193 PGP Key Fingerprint: 8F06 5A2E 2735 892B 821C 871A 0411 94EA DB02 E193

CPallini

krmed wrote:

Well, perhaps that would be ok, but if the file size is large (2 GB) the new of a 2GB char array would probably fail, and you don't need anywhere near that many characters to hold a file size.

Of course the buffer can't be sized equal to file dimension, have you missed my aknowledge about your point? That stated, my post completely agree with your bottom line:

krmed wrote:

Perhaps a fixed buffer size of say [MAX_PATH_LEN] (which is 256) would be more than enough characters to hold any file size.

:)

If the Lord God Almighty had consulted me before embarking upon the Creation, I would have recommended something simpler. -- Alfonso the Wise, 13th Century King of Castile.

krmed

Sorry if you thought I meant that all at you. Actually, I was agreeing with the fixed size, but wanted the OP to realize that he probably can't new a char array the size of the file length (and it wouldn't be needed anyway). I was simply suggesting that a fixed size (like you said) would work, and MAX_PATH_LEN would be more than enough - in fact 20 characters will hold more than ever needed. Have a great day!

Karl - WK5M PP-ASEL-IA (N43CS) PGP Key: 0xDB02E193 PGP Key Fingerprint: 8F06 5A2E 2735 892B 821C 871A 0411 94EA DB02 E193

krmed

You're right about the len in the printed string - my turn to not think clearly about what he's doing!

Karl - WK5M PP-ASEL-IA (N43CS) PGP Key: 0xDB02E193 PGP Key Fingerprint: 8F06 5A2E 2735 892B 821C 871A 0411 94EA DB02 E193

Mark Salsbery

and in addition to DavidCrow's reply... Since you're using MFC and a CString, which is a generic string type, use generic literals as well...

CString len_str;
len_str.Format(_T("%d"), len);

Mark Salsbery Microsoft MVP - Visual C++ :java:

Hamid Taebi

You can assign your value to control with Set SetDlgItemInt and you dont need to other variables.