Comments on Senzee 5: Formatting std::string

thanks a lot! i'd just like to add one function t...

2010-03-09T11:13:43.089-05:00

thanks a lot!

i'd just like to add one function to pass the first length of result to try :)

std::string format_arg_list(DWORD dwdResLenToTryFirst,const char *fmt, va_list args)
{
if(!fmt)return"";
int result=-1;
int length=dwdResLenToTryFirst;
char *buffer=0;
while(result==-1)
{
if(buffer)delete[]buffer;
buffer=new char[length+1];
memset(buffer,0,length+1);
result=_vsnprintf(buffer,length,fmt,args);
length *= 2;
}
std::string s(buffer);
delete[]buffer;
return s;
}

std::string format(const char *fmt, ...)
{
va_list args;
va_start(args, fmt);
std::string s=format_arg_list(256,fmt,args);
va_end(args);
return s;
}

std::string formatLen(DWORD dwdResLenToTryFirst,const char *fmt, ...)
{
va_list args;
va_start(args, fmt);
std::string s=format_arg_list(dwdResLenToTryFirst,fmt,args);
va_end(args);
return s;
}

If you are using VC, the _vsctprintf function will...

2010-02-09T00:44:08.333-05:00

If you are using VC, the _vsctprintf function will give you the length need to store the resulting string, and you can get rid of the loop.

It's so great that std::string doesn't have format...

2010-01-20T11:59:35.917-05:00

It's so great that std::string doesn't have formatting. Just another evidence that c++ designers hadn't coded a single line in ten years.

My expectation level for tr1 is even higher, it so promising that I'll probably change C++ for cobol, or something worse.

it's gcc ver.. http://blog.yurihan.net/entry/stds...

2009-09-23T11:34:23.624-04:00

it's gcc ver..

http://blog.yurihan.net/entry/stdstring%EC%9D%98-formating-%EC%8B%9C%EB%B0%9C-%EB%82%9A%EC%98%80%EB%8B%A4

Thanks a million!!

2009-03-20T02:56:00.000-04:00

Thanks a million!!

Exactly what I was looking for ...Thank you !

2009-01-19T11:40:00.000-05:00

Exactly what I was looking for ...

Thank you !

Thanks! This is great!

2008-01-27T09:07:00.000-05:00

Thanks! This is great!

As you say, it's not the most efficient piece of c...

2007-11-30T17:08:00.000-05:00

As you say, it's not the most efficient piece of code, but it is just in turn of a very nice and simple usage, just what I was looking for...

Thank you very much!!

Thanks. What a nice!In visual Studio 2005, this co...

2007-10-25T06:12:00.000-04:00

Thanks. What a nice!
In visual Studio 2005, this code meets deprecate warning.
So, I replace _vsnprintf to _vsprintf_s

code :
result = _vsnprintf_s(buffer, length, _TRUNCATE, fmt, args);

Because the return type is [std::string] and not [...

2007-07-26T10:45:00.000-04:00

Because the return type is [std::string] and not [std::string &] (or [std::string *]), it is return by value. So, upon return, it will create a copy of the stack variable s in the caller's scope.

So it's completely safe.

Keep in mind however, that this is not an efficient piece of code. It's brute force and requires a number of allocations. Still, it's convenient, and that's often more important than efficiency.

Regarding the earlier comment about not supporting unicode - that's true, but little modification is required for unicode support, such as using std::basic_string<wchar_t> instead of std::string and using the appropriate wide character formatting function.

std::string s(buffer); delete [] buffer; ret...

2007-07-26T04:59:00.000-04:00

std::string s(buffer); delete [] buffer; return s;
}

Won't that give problems? Isn't "s" created on the heap and no longer guaranteed when the function returns (although it will _probably_ be there , just cos it isn't overwritten yet (espeically in non-threaded programs))?

Does your compiler give warnigs? Did you run Lint on it?

cool, but it seems that doest not support UNICODE....

2007-06-11T07:46:00.000-04:00

cool, but it seems that doest not support UNICODE.

Thanks, not exactly how I thought it would be solv...

2006-11-29T19:18:00.000-05:00

Thanks, not exactly how I thought it would be solved. But it works. Thanks.

Very nice piece of code. Saved me some time. Many ...

2006-09-10T14:55:00.000-04:00

Very nice piece of code. Saved me some time. Many thanks!