ex11_3_4.cpp

// @Yue Wang Aug, 2015
//
// Exercise 11.3:
// Write your own version of the word-counting program.
//
// Exercise 11.4:
// Extend your program to ignore case and punctuation.
// For example, “example.” “example, ” and “Example” should
// all increment the same counter.
//

#include <iostream>
#include <map>
#include <string>
#include <algorithm>
#include <cctype>

using Map = std::map<std::string, std::size_t>;

//for ex11.3
auto count() -> Map
{
    Map counts;
    for (std::string w; std::cin >> w; ++counts[w]);
    return counts;
}

//for ex11.4
auto strip(std::string& str) -> std::string const&
{
    for (auto& ch : str) ch = tolower(ch);
    str.erase(std::remove_if(str.begin(), str.end(), ispunct), str.end());
    return str;
}

//for ex11.4
auto strip_and_count() -> Map
{
    Map counts;
    for (std::string w; std::cin >> w; ++counts[strip(w)]);
    return counts;
}

auto print(Map const& m) -> std::ostream&
{
    for (auto const& kv : m)
        std::cout << kv.first << " : " << kv.second << "\n";
    return std::cout;
}

int main()
{
    std::cout << "[ex11.3] Enter a few words please:\n";
    print( count() );
    std::cin.clear();
    std::cout << "[ex11.4] Enter a few words please:\n";
    print( strip_and_count() );

    return 0;
}