Exer14_39.cpp

#include <iostream>
#include <fstream>
#include <string>
#include <vector>
#include <algorithm>
using std::cout;
using std::endl;
using std::ifstream;
using std::string;
using std::vector;
class InRange {
public:
    InRange(string::size_type d, string::size_type u) : down(d), up(u) {}
    bool operator()(const string& s) const
        { return s.size() >= down && s.size() <= up; }
private:
    string::size_type down;
    string::size_type up;
};
int main(int argc, char* argv[])
{
    if(argc != 2)
        return -1;
    ifstream file(argv[1]);
    string word;
    vector<string> text;
    while(file >> word)
        text.push_back(word);
    for(string::size_type upper = 2; upper != 20; ++upper)
    {
        auto cnt = count_if(text.cbegin(), text.cend(), InRange(1, upper));
        cout << "There are " << cnt
             << " words whose length between 1 and " << upper
             <<" inclusive" << endl;
    }
    return 0;
}