Equivalent of %02d with std::stringstream?
I want to output an integer to a std::stringstream
with the equivalent format of printf
's %02d
. Is there an easier way to achieve this than:
std::stringstream stream;
stream.setfill('0');
stream.setw(2);
stream << value;
Is it possible to stream some sort of format flags to the stringstream
, something like (pseudocode):
stream << flags("%02d") << value;
You can use the standard manipulators from <iomanip>
but there isn't a neat one that does both fill
and width
at once:
stream << std::setfill('0') << std::setw(2) << value;
It wouldn't be hard to write your own object that when inserted into the stream performed both functions:
stream << myfillandw( '0', 2 ) << value;
E.g.
struct myfillandw
{
myfillandw( char f, int w )
: fill(f), width(w) {}
char fill;
int width;
};
std::ostream& operator<<( std::ostream& o, const myfillandw& a )
{
o.fill( a.fill );
o.width( a.width );
return o;
}
You can use
stream<<setfill('0')<<setw(2)<<value;