Truncate std__ostringstream?

[MikeCopeland]

Is there a way to truncate 1 or more characters from a constructed
std::ostringstream? I have situations where I build a stream
(data_value1, comma, data_value2, comma, etc.) and when complete I want
to erase the last comma before I process the constructed variable.
Currently, I convert the stream to a std::string and erase the last
character, but that's clumsy.
Can I do this while it's an ostringstream? Please advise. TIA


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[Alf P. Steinbach]

On 03.06.2016 02:45, MikeCopeland wrote:
> Is there a way to truncate 1 or more characters from a constructed
> std::ostringstream? I have situations where I build a stream
> (data_value1, comma, data_value2, comma, etc.) and when complete I want
> to erase the last comma before I process the constructed variable.
> Currently, I convert the stream to a std::string and erase the last
> character, but that's clumsy.
> Can I do this while it's an ostringstream? Please advise. TIA

You can change the logic used to put items into the ostream, like this:

int n_written = 0;
for( auto const& item : items )
{
if( n_written > 0 ) { stream << ", "; }
stream << item;
++n_written;
}

Cheers & hth.,

- Alf