Count words in a file

By default, the basic_istream class reads one word at a time. We can take advantage of this property to use an istream_iterator to count words.

How to do it…

This is a simple recipe to count words using an istream_iterator:

• We'll start with a simple function to count words using an istream_iterator object:

  size_t wordcount(auto& is) {
      using it_t = istream_iterator<string>;
      return distance(it_t{is}, it_t{});
  }

The distance() function takes two iterators and returns the number of steps between them. The using statement creates an alias it_t for the istream_iterator class with a string specialization. We then call distance() with an iterator, initialized with the input stream it_t{is}, and another with the default constructor, which gives us an end-of-stream sentinel.

• We call wordcount() from main():

  int main() {
      const char * fn{ "the-raven...