Is there a way to implement analog of Python's 'separator'.join() in C++?

Question

All I\'ve found is boost::algorithm::string::join. However, it seems like overkill to use Boost only for join. So maybe there are some time-tested recipes?

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Answer 1

Since you're looking for a recipe, go ahead and use the one from Boost. Once you get past all the genericity, it's not too complicated:

1. Allocate a place to store the result.
2. Add the first element of the sequence to the result.
3. While there are additional elements, append the separator and the next element to the result.
4. Return the result.

Here's a version that works on two iterators (as opposed to the Boost version, which operates on a range.

template 
std::string join(Iter begin, Iter end, std::string const& separator)
{
  std::ostringstream result;
  if (begin != end)
    result << *begin++;
  while (begin != end)
    result << separator << *begin++;
  return result.str();
}