Re: vsprintf in std

From:
"Tom Widmer [VC++ MVP]" <tom_usenet@hotmail.com>
Newsgroups:
microsoft.public.vc.language
Date:
Tue, 26 Jun 2007 14:48:50 +0100
Message-ID:
<#Bzp7i$tHHA.484@TK2MSFTNGP06.phx.gbl>
Jack wrote:

"Jack" <jl@knight.com> ???g???l???s?D:ui47luxtHHA.3688@TK2MSFTNGP03.phx.gbl...

"Jack" <jl@knight.com> ???g???l???s?D:OCdbfXvtHHA.4424@TK2MSFTNGP04.phx.gbl...

Hello,
I have been searching in help but I found that was hard to search.
What I looking for was the std counterpart of CRT vsprintf. :)
I did find something like std::vsprintf in help, but still not sure about
how to use it

original code with CRT,
vsprintf (strTab->str[strTab->numLines], format, args);

Any help is greatly appreciated
Thanks
Jack

I devised a new way :)
void appendStrTab (strTable *strTab, char *format, ...)
{
va_list args;
char o[100];

va_start (args, format); // Jack unmanaged
strTab->str.append("\n");
vsprintf ((char *)o , format, args);
strTab->str.append(o);
strTab->numLines++;
va_end(args);
}

Looks better? :)
It compiles okay.....
Thanks
Jack


I think the ultimate way is to define strTab like this.... agree?

typedef struct {


typedef struct is a C-ism - you shouldn't use it in C++ code.

         dword numLines;
         std::vector<std:strstream> w;
} strTable;


You should probably just have:

struct strTable
{
   std::vector<std:string> lines;
};

But how do I access say the first element of the string array?

void appendStrTab (strTable *strTab, char *format, ...)
{
 va_list args;
// char o[100];

 va_start (args, format); // Jack unmanaged


//get the length, to prevent any possibility of buffer overrun.
int count = _vscprintf(format, args);
std::vector<char> buffer(count + 1);

// strTab->str.append("\n");
 vsprintf ((char *)o[strTab->numLines].str() , format, args); // C2228


vsprintf(&buffer[0], format, args);

strTab->lines.push_back(std::string(buffer.begin(), buffer.end() - 1));

// strTab->str.append(o);
 strTab->numLines++;


numLines is redundant, since it would be equal to strTab->lines.size().

 va_end(args);
}


Tom

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