小编Rec*_*ent的帖子

我正在尝试为operator<<标准库容器的特定实例化编写重载,这些容器将存储在boost::variant.这是一个说明问题的小例子:

#include <iostream>
#include <vector>

std::ostream & operator<<( std::ostream & os, const std::vector< int > & ) {
  os << "Streaming out std::vector< int >";
  return os;
}

std::ostream & operator<<( std::ostream & os, const std::vector< double > & ) {
  os << "Streaming out std::vector< double >";
  return os;
}

#include <boost/variant.hpp>

typedef boost::variant< std::vector< int >, std::vector< double > > MyVariant;

int main( int argc, char * argv[] ) {
  std::cout << MyVariant();
  return …