Earliest date search with Suggesting file name and "automat"

#include "stdafx.h"
#include <fstream>
#include <iostream>
#include <string>
#include <vector>
#include <algorithm>
#include <regex>
#include <streambuf>
#include <filesystem>

int matrix[3][10] =
{ //S, A1, A2, A3, A4, A5, A6, A7, A8, A9
    1, 2,  0,  4,  5,  0,  7,  8,  9,  10, //A for 0-9
    0, 0,  3,  0,  0,  6,  0,  0,  0,  0,  //A for "-./"
    0, 0,  0,  0,  0,  0,  0,  0,  0,  0,  //S for everything else
};

int row(char& a)
{
    if (a >= '0' && a <= '9')
        return 0;
    if (a == '.' || a == '-' || a == '/')
        return 1;
    return 2;
}

void auto_rifle(std::string& str, std::string& str_out)
{
    std::string date = "";
    int state = 0;
    for (unsigned long long k = 0; k < str.size(); k++)
    {
        if (state == 0)
            date.clear();
        state = matrix[(row(str[k]))][state];
        date.push_back(str[k]);
        if (state == 10)
        {
            str_out += date + " ";
            state = 0;
        }
    }
    return;
}

template <typename T>
typename T::size_type levenshtein_distance(const T & src, const T & dst)
{
    const typename T::size_type m = src.size();
    const typename T::size_type n = dst.size();
    if (m == 0)
    {
        return n;
    }
    if (n == 0)
    {
        return m;
    }

    std::vector<std::vector<typename T::size_type>> matrix(m + 1);

    for (typename T::size_type i = 0; i <= m; ++i)
    {
        matrix[i].resize(n + 1);
        matrix[i][0] = i;
    }
    for (typename T::size_type i = 0; i <= n; ++i)
    {
        matrix[0][i] = i;
    }

    typename T::size_type above_cell, left_cell, diagonal_cell, cost;

    for (typename T::size_type i = 1; i <= m; ++i)
    {
        for (typename T::size_type j = 1; j <= n; ++j)
        {
            cost = src[i - 1] == dst[j - 1] ? 0 : 1;
            above_cell = matrix[i - 1][j];
            left_cell = matrix[i][j - 1];
            diagonal_cell = matrix[i - 1][j - 1];
            matrix[i][j] = std::min(std::min(above_cell + 1, left_cell + 1), diagonal_cell + cost);
        }
    }

    return matrix[m][n];
}

#include <Windows.h>

using namespace std;
using namespace experimental::filesystem;

HANDLE hConsole = GetStdHandle(STD_OUTPUT_HANDLE);

inline bool print_str(string str, int k, int n)
{
    SetConsoleTextAttribute(hConsole, k);
    for (int l = 0; l < int(str.size()); l++)
    {
        cout << str[l];
        Sleep(n);
    }
    SetConsoleTextAttribute(hConsole, 14);
    return true;
}

bool yes_no()
{
    bool err = false;
    string temp;
    getline(cin, temp);
    do
    {
        err = false;
        if (temp == "Yes" || temp == "yes" || temp == "y" || temp == "Y") return true; // Returning result for yes answer
        else if (temp == "No" || temp == "no" || temp == "N" || temp == "n") return false; // For no answer
        else
        {
            // If input is incorrect
            print_str("Type [Yes] or [No]: ", 15, 15);
            getline(cin, temp);
            err = true;
        }
    }
    while (err);
    cout << "An error occurred!" << endl;
    return true;
}

bool yes_no(const string& str)
{
    bool err = false;
    print_str(str, 15, 10);
    string temp;
    getline(cin, temp);
    do
    {
        err = false;
        if (temp == "Yes" || temp == "yes" || temp == "y" || temp == "Y") return true; // Returning result for yes answer
        else if (temp == "No" || temp == "no" || temp == "N" || temp == "n") return false; // For no answer
        else
        {
            // If input is incorrect
            print_str("Type [Yes] or [No]: ", 15, 15);
            getline(cin, temp);
            err = true;
        }
    }
    while (err);
    cout << "An error occurred!" << endl;
    return true;
}

string make_path(string str)
{
    string extension = "";
    unsigned int j;
    if (str.length() >= 4)
    {
        j = str.length() - 4;
        for (int i = 0; i < 4; i++)
        {
            extension.push_back(str[j]);
            j++;
        }
    }
    if (extension == ".txt")
        str = "Books/" + str;
    else
        str = "Books/" + str + ".txt";
    return str;
}

void filling_strings(vector<string>& vec)
{
    unsigned int max_l = 0;
    for (unsigned int i = 0; i < vec.size(); i++)
    {
        if (vec[i].length() > max_l)
            max_l = vec[i].size();
    }
    for (unsigned int i = 0; i < vec.size(); i++)
    {
        while (vec[i].length() < max_l)
            vec[i].push_back(' ');
    }
}

string shorting_string(string str)
{
    while (str[str.length() - 1] == ' ')
        str.pop_back();
    return str;
}

string vec_search(const vector<string>& vec, const string& str)
{
    unsigned int i = 0, k = 0, dist = 100;
    while (k < vec.size())
    {
        if (levenshtein_distance(vec[k], str) < dist)
        {
            dist = levenshtein_distance(vec[k], str);
            i = k;
        }
        k++;
    }
    return vec[i];
}

void regex_result(string& str, vector<string>& vec, const regex& rgx)
{
    regex_token_iterator<string::iterator> rend;
    regex_token_iterator<string::iterator> a(str.begin(), str.end(), rgx);
    while (a != rend) vec.push_back(*a++);
}

bool empty(const string& str)
{
    bool empty = true;
    if (!str.empty())
    {
        for (unsigned int i = 0; i < str.length(); i++)
        {
            if (str[i] != ' ')
            {
                empty = false;
            }
        }
    }
    return empty;
}

void files(vector<string>& vec)
{
    for (auto p : directory_iterator("Books"))
    {
        vec.push_back(p.path().string());
    }
    filling_strings(vec);
}

void check_files(vector<string>& vec)
{
    unsigned int i;
    vector<string> vec_2;
    bool same_name = true;
    for (auto p : directory_iterator("Books"))
    {
        vec_2.push_back(p.path().string());
    }
    filling_strings(vec_2);
    if (vec_2.size() != vec.size())
    {
        vec.clear();
        vec = vec_2;
        filling_strings(vec);
    }
    else
    {
        if (vec.size() > vec_2.size())
            i = vec_2.size();
        else
            i = vec.size();
        for (unsigned j = 0; j < i; j++)
        {
            if (vec[j] != vec_2[j])
            {
                vec = vec_2;
                return;
            }
        }
    }
}

int main()
{
    print_str(
        "Hello user!\
    \nThis is a program for loading files and searching for earliest date in them. \
    I am your personal assistant, AI Cortana.\
    \nI have few featerues like: \n",
        3, 5);
    print_str(
        "1. Finding existing date (within 32 days and month and more than 12 months) \nincluding leap years;\
    \n2. Suggesting file names if input was incorrect (Pretty unstable, needs \nto be modified);\
    \n3. Looping for easy multiple requests.\
    \nHave fun!\n",
        10, 5);
    smatch match;
    regex date(
        "(((0[1-9]|[12][0-9]|3[01])[-/.](0[13578]|1[02])|(0[1-9]|[12][0-9]|30)[-/.](0[469]|11)|(0[1-9]|1\\d|2[0-8])[-/.]02)[-/.]\\d{4}|29[-/.]02[-/.](\\d{2}(0[48]|[2468][048]|[13579][26])|([02468][048]|[1359][26])00))",
        regex_constants::nosubs);
    vector<string> books, dates;
    files(books);
    string file, read;
    do
    {
        print_str("Write file's name: ", 15, 10);
        do
        {
            getline(cin, file);
        }
        while (empty(file) && cout << "Why would you write nothing? Type again: ");
        ifstream in;
        check_files(books);
        dates.clear();
        in.open(make_path(file));
        if (!in.is_open())
        {
            print_str("Did you mean \"", 15, 10);
            cout << shorting_string(vec_search(books, make_path(file)));
            print_str("\"?\n", 15, 10);
            if (yes_no())
                in.open(vec_search(books, make_path(file)));
        }
        read.assign((istreambuf_iterator<char>(in)),
                    istreambuf_iterator<char>());
        string auto_dates = "";
        auto_rifle(read, auto_dates);
        regex_result(auto_dates, dates, date);
        if (!in.is_open())
            print_str("Couldn't load the file.\n", 7, 10);
        else if (dates.empty())
            print_str("There is no dates in this text file.\n", 15, 10);
        else
        {
            string final_date = dates[0];
            for (unsigned int i = 1; i < dates.size(); i++)
            {
                int k = 0;
                int j = dates[i].length() - 4;
                while (final_date[j] == dates[i][j])
                {
                    if (j == dates[i].length() - 1)
                    {
                        j -= 7;
                    }
                    if (j == dates[i].length() - 6)
                    {
                        j -= 4;
                        k++;
                        if (k == 2)
                            break;
                    }
                    j++;
                }
                if (final_date[j] > dates[i][j])
                    final_date = dates[i];
            }
            print_str("The earliest date is ", 15, 15);
            cout << final_date << endl;
        }
        in.close();
    }
    while (yes_no("Do you want to continue?\n"));
}