Skipping in Range-based for based on 'index'?

Question

Is there a way to access the iterator (suppose there\'s no loop index..?) in a C++11 range-based for loop?

Often we need to do something special with the fi

Answer 1

When I need to do something like this on a random access container, my habit is to iterate over the indexes.

for( std::size_t i : indexes( container ) ) {
  if (i==0) continue;
  auto&& e = container[i];
  // code
}

the only tricky part is writing indexes, which returns a range of what boost calls counting iterators. Creating a basic iterable range from iterators is easy: either use boost's range concept, or roll your own.

A basic range for an arbitrary iterator type is:

template
struct Range {
  Iterator b; Iterator e;
  Range( Iterator b_, Iterator e_ ):b(b_), e(e_) {};
  Iterator begin() const { return b; }
  Iterator end() const { return e; }
};

which you can gussy up a bunch, but that is the core.