Is there an STL algorithm or other such template that will allow printf-type
formatting of std::string & std::wstring objects.

What I would like to do is some like:-

        std::string strAge;
        strAge.format("%03d", nAgeVar);

or more likely

        std::string strAge;
        format(strAge, "%03d", nAgeVar);

Rod Paterson

    There is nothing printf-like in C++, because printf is hopelessly
limited to C data types.   How would you use printf to display a Employee
object?

    The C++ solution:

    stringstream    s;

    s << nAgeVar;

    All the formatters that work with cout will work with a stringstream.

Rod,

Here is a rough example of a global function which takes a std::string, a
format string, and a variable number of arguments and formats the string
appropriately.  This should suit your needs.   You could always write
another one which takes a std::wstring

(On the other hand, if you're really looking for a std::basic_string
derivative which has this CString like functionality, you could also try
something I wrote a while back
http://home.earthlink.net/~jmoleary/stdstring.htm)

Joe O'

    void FormatString(std::string& str, LPCSTR* szFormat, ...)
    {
        va_list argList;
        va_start(argList, szFormat);
        FormatStringV(str, szFormat, argList);
        va_end(argList);
    }

   #define MAX_FMT_TRIES 5  // #of times we try if 2048 chars isn't big
enough
   #define FMT_BLOCK_SIZE 2048 // amount of extra memory we'll add above
2048 each try

   void FormatStringV(std::string& str, LPCSTR szFormat, va_list argList)
   {
       va_list argListSave = argList;

       // We'll use the  _vsntprintf function, assuming FMT_BLOCK_SIZE
characters.

       int nTriesLeft   = MAX_FMT_TRIES;
       int nUsed  = -1;
       char* pBuf;

      int nChars = 0;

       // Keep looping until we succeed or we have exhausted the number of
tries

       do
       {
           nChars += FMT_BLOCK_SIZE;  // number of TCHARS in the string
           pBuf  = reinterpret_cast<LPCSTR>(_alloca(nChars));

           // Now try the actual formatting.

           nUsed = _vsntprintf(pBuf, nChars, szFormat, argListSave);

           if ( nUsed >= 0 )
              str = pBuf;

          } while ( nUsed < 0 && --nTriesLeft > 0);

          va_end(argListSave);
      }
   }

printf formatting is a disease, and C++ contains the
cure (iostreams).

Not trying to be confrontational.  A solution which
you may find helpful has already been posted, but I
would submit for your consideration that you try
iostreams (following is ISO standard C++ and works
with VC6):

#include <iomanip>
#include <iostream>b
#include <sstream>

std::stringstream  ss;
int  AgeVar = 7;
ss << std::setw(3) << AgeVar;
std::cout << ss.str() << std::endl;

For what it's worth, I prefer iostreams as well.  It's just that in some
projects I've worked on, I've had to integrate with legacy code that used
old, CRT iostreams which tend to conflict with the new C++ ones.  Since he
asked specifically for printf-style printing, that's what I gave him.

But Rod you should defnitely use iostreams if you can..  They'll save you
from many silly errors.

Joe O'