CODEWITHSUNDEEP
c++streamoverloading
jav974
jav974

Reputation: 1042

c++ get stream modifier from << overload

I have overloaded the stream insertion operator like this :

template<class Ch, class Tr, class word_type>
std::basic_ostream<Ch, Tr>&
operator << (std::basic_ostream<Ch, Tr>& s, const Mabit::mabit<word_type>& obj)
{
  s << obj.to_string(Mabit::DEC, ',');
  return s;
}

(mabit being the class for which i wanted the overload to work)

That is, since i can give different argument to the to_string method, i would like to be able to use standard stream modifier like std::dec, std::hex ... in a way that i could retrieve them from the overloaded operator to prepare the good argument as parameter for to_string

If i could also get the locale being used (to extract the separator for thousands) , it would be helpfull for the second argument too...

Is that possible ?

Upvotes: 3

Views: 256

Answers (2)

AlexK
AlexK

Reputation: 1281

From http://www.cplusplus.com/reference/locale/numpunct/thousands_sep/

#include <iostream>
#include <locale>
using namespace std;

int main ()
{
  int q=10977;
  char separator = use_facet<numpunct<char> >(cout.getloc()).thousands_sep ();
  cout << q/1000 << separator << q%1000 << endl;
  return 0;
}

I suppose you can just replace cout with your stream argument in this example

Upvotes: 1

Steven Maitlall
Steven Maitlall

Reputation: 787

You can use std::basic_ostream::flags() to identify whether an format specifier was used.

http://en.cppreference.com/w/cpp/io/ios_base/flags

Upvotes: 5

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