Re: counting words in input

NoSpam@NoPain.com says...

[ ... ]


People have already talked quite a bit about the part you really asked
about, but I thought I'd add a slightly different approach to the task
itself:

#include <iostream>
#include <set>
#include <algorithm>
#include <string>

class shorter_than {
    size_t x;
public:
    shorter_than(size_t c) : x(c) {}

    bool operator()(std::string const &s) {
        return s.length() < x;
    }
};

int main() {
    std::set<std::string> words;

    std::remove_copy_if(
        std::istream_iterator<std::string>(std::cin),
        std::istream_iterator<std::string>(),
        std::inserter(words, words.begin()),
        shorter_than(4));

    std::cout << words.size() << " unique words:\n";
    std::copy(words.begin(), words.end(),
        std::ostream_iterator<std::string>(std::cout, "\n"));
    return 0;
}

std::remove_copy_if copies one container to another, leaving out any
that meet the specified criteria. std::set only allows one copy of a
specific item to be inserted, so each one is automatically unique,
without explicitly removing duplicates.