Kursova

/**
 * \brief A program that uses files as database for operating a football players card-index.
 *
 * This program has the functionality of:
 *      - Adding new players
 *      - Searching players by ID
 *      - Searching players by Country
 *      - Outputting all players
 *      - Modifying goals scored by player's last name and country
 *
 * Things that can be added:
 *      - Removing from file
 *      - Modifying other player data, such as name, country, etc.
 *      - More searching methods, such as by name, last_name, goals scored, etc.
 *      - A lot of tweaks could be done to the player information
 *      - etc...
 *
 * \version: 1.0
 *
 * \date 2018/12/12 13:44:06
 *
 */
#include <iostream>
#include <string>
#include <vector>

#include <fstream>

#include <conio.h>

using namespace std;

/*!
 * A structure that contains the Football Player information
 */
struct Player {
    string first_name;
    string last_name;
    string country;

    size_t id;
    size_t scored_goals;
};

/*!
 * \brief This function asks the user to input data, makes some checks
 *      and if the checks pass, saves the information to a file named
 *      players.dat by converting the struct into binary code.
 *
 * \param Player An array of custom data structure representing the data, may be
 *      empty, but not null.
 * \param array_size A std::size_t defined variable used for the number of elements
 *      in the array we mentioned earlier (Player array).
 *
 * \see std::size_t
 * \see auto specifier
 */
auto input(Player* array, size_t array_size) -> void;

/*!
 * \brief This function gets the information from the binary file and converts
 *      it to its' representative data type and variable name of the structure.
 *      It is the core function of the queries as well. As long as you understand
 *      how this function works, the others will seem like they are the same.
 *      (which they are, I just copied them from this function and added up more
 *      features).
 *
 * \param Player An array of custom data structure representing the data, may be
 *      empty, but not null.
 *
 * \see auto specifier
 */
auto output(Player* array) -> void;

/*!
 * \brief This function gets the information from the binary file and converts
 *      it to its' representative data type and variable name of the structure
 *      by a specific argument.In this example, we are using the ID to search
 *      for the player(s) we want to show. The function itself asks the user to
 *      input a player ID that he wants to search for in the file.
 *
 *      For in-depth understanding, look at QueryByCountry function
 *
 * \param Player An array of custom data structure representing the data, may be
 *      empty, but not null.
 *
 * \see auto specifier
 * \see QueryByCountry
 */
auto QueryById(Player* array) -> void;

/*!
 * \brief This function gets the information from the binary file and converts
 *      it to its' representative data type and variable name of the structure
 *      by a specific argument.In this example, we are using the country to search
 *      for the player(s) we want to show. The function itself asks the user to
 *      input a player country that he wants to search for in the file.
 *
 *      For in-depth understanding, look at QueryByCountry function
 *
 * \param Player An array of custom data structure representing the data, may be
 *      empty, but not null.
 *
 * \see std::size_t
 * \see auto specifier
 */
auto QueryByCountry(Player* array) -> void;

/*!
 * \brief This function modifies the information from the binary file and converts
 *      it to its' representative data type and variable name of the structure
 *      by a specific argument.In this example, we are using the players' country
 *      and the players' last name to search for the player(s) we want to modify.
 *      The function itself asks the user to input the player's country and
 *      last name that he wants to search for in the file. Then if any records are
 *      found, asks the user to enter goals scored. The goals scored has validation
 *      check. If this check is passed, modifies the current player's goals scored.
 *      If multiple players found with this country and last name, modifies them
 *      one by one by the algorithm described above.
 *
 *      For in-depth understanding, look at QueryByCountry function
 *
 * \param Player An array of custom data structure representing the data, may be
 *      empty, but not null.
 *
 * \see std::size_t
 * \see auto specifier
 */
auto ModifyData(Player* array) -> void;

/*!
 * The main function which contains:
 *  - A menu of choices for each function with the file. You can easily do:
 *      -# Inputting data into file
 *      -# Outputting the information from the file
 *      -# Querying players by ID
 *      -# Querying players by Country
 *      -# Modifying goals scored on each player, queried by last name and country
 *
 * \brief The main function has been realized with pointers and dynamically allocation of
 *      array. It has checks, that disallow negative data being used. It uses files to
 *      store the information that has been passed and used in the program.
 *
 * \return int
 *
 * \see input
 * \see output
 * \see QueryById
 * \see QueryByCountry
 * \see ModifyData
 */
int main()
{
    size_t choice, array_size(30);

    /// Setting initial value different than null, because of fread function
    Player* array = new Player[array_size];

    do {
        system("cls");

        cout << "Menu: \n";
        cout << "[1] Input players\n";
        cout << "[2] Output Players\n";
        cout << "[3] Query players by ID\n";
        cout << "[4] Query players by Country\n";
        cout << "[5] Modify player data, queried by name and last name\n\n";
        cout << "[0] Exit\n";

        cout << "Make your choice: ";
        cin >> choice;

        switch (choice) {
            case 1:
                system("cls");

                do {
                    cout << "Enter number of players u want to input: ";
                    cin >> array_size;

                } while (array_size <= 0);

                array = new Player[array_size];

                input(array, array_size);

                cout << "\n\nEnter any key to get back to the menu...\n";
                _getch();

                break;
            case 2:
                system("cls");

                output(array);

                cout << "\n\nEnter any key to get back to the menu...\n";
                _getch();

                break;
            case 3:
                system("cls");

                QueryById(array);

                cout << "\n\nEnter any key to get back to the menu...\n";
                _getch();

                break;

            case 4:
                system("cls");
                cin.ignore();

                QueryByCountry(array);


                cout << "\n\nEnter any key to get back to the menu...\n";
                _getch();

                break;

            case 5:
                system("cls");

                ModifyData(array);

                cout << "\n\nEnter any key to get back to the menu...\n";
                _getch();

                break;
        }
    } while (choice != 0);

    /// Clearing the memory we used
    delete []array;

    return 0;
}

auto input(Player* array, size_t array_size) -> void {

    fstream file("players.dat", ios::binary | ios::out);

    for (size_t i = 0; i < array_size; i++) {
        cout << "Enter first name: ";
        cin >> array[i].first_name;

        cout << "Enter last name: ";
        cin >> array[i].last_name;

        cin.ignore();

        cout << "Enter country: ";
        getline(cin, array[i].country);


        do {
            cout << "Enter player id: ";
            cin >> array[i].id;
        } while (array[i].id < 0);

        do {
            cout << "Enter scored goals: ";
            cin >> array[i].scored_goals;
        } while (array[i].scored_goals < 0);
    }

    file.write((char *)array, array_size * sizeof(Player));
    file.close();
}

auto output(Player* array) -> void {
    /// Opening the file players.dat as binary for reading
    fstream file("players.dat", ios::binary | ios::in);

    /// Check if the file is present, else exits
    if (!file) {
        cout << "File not found!\n";
        exit(0);
    }
    else {
        /// Goes to the end of the file
        file.seekg(0L, ios::end);

        /// Gets the byte size of the whole file
        auto pos = file.tellg();

        /*!
         * Calculate the needed size of the array.
         *
         * How? We have the file byte size and our struct
         *      represents just one item from our array.
         *      To get our array size, we need to divide
         *      the byte size of the file, where we stored
         *      the array of Player, and the size in bytes
         *      of our struct Player, thus: sizeof(Player).
         *
         * \see Player
         */
        auto array_size = pos / sizeof(Player);

        /// Getting back to the beginning of the file to read it
        file.seekg(0L, ios::beg);

        /*!
         * Reading the whole file, because we have array_size * sizeof(Player),
         *      as a constant string(char *), and writing it by its' places in the struct.
         *      - id from the file goes to id from the struct
         *      - first_name from the file goes to first_name from the struct
         *      - etc...
         *
         * \see Player
         */
        file.read((char *) array, array_size * sizeof(Player));

        /// Iterating through the array and outputting the information
        for (size_t i = 0; i < array_size; i++) {
            cout << "ID: " << array[i].id << endl;
            cout << "First Name: " << array[i].first_name << endl;
            cout << "Last Name: " << array[i].last_name << endl;
            cout << "Country: " << array[i].country << endl;
            cout << "Goals scored: " << array[i].scored_goals << endl;

            cout << "\n\n----------------------------------------------\n\n";
        }
    }

    /// Closing the file
    file.close();
}

auto QueryById(Player* array) -> void {

    size_t id, counter(0);

    cout << "Enter ID you want to search for: ";
    cin >> id;

    fstream file("players.dat", ios::binary | ios::in);

    if (!file) {
        cout << "File not found!\n";
        exit(0);
    }
    else {
        file.seekg(0L, ios::end);

        auto pos = file.tellg();
        auto array_size = pos / sizeof(Player);

        file.seekg(0L, ios::beg);

        file.read((char *)array, array_size * sizeof(Player));

        for (size_t i = 0; i < array_size; i++) {
            if (array[i].id == id) {
                cout << "ID: " << array[i].id << endl;
                cout << "First Name: " << array[i].first_name << endl;
                cout << "Last Name: " << array[i].last_name << endl;
                cout << "Country: " << array[i].country << endl;
                cout << "Goals scored: " << array[i].scored_goals << endl;

                counter++;
            }

            cout << "\n\n----------------------------------------------\n\n";
        }
    }

    if (counter == 0) {
        cout << "No players with this id found!\n\n";
    }

    file.close();
}

auto QueryByCountry(Player* array) -> void {

    /// Used for user input
    char choice;
    string country;

    /// Counter used for information only
    size_t counter(0);

    /// Opening the file players.dat as binary for reading
    fstream file("players.dat", ios::binary | ios::in);

    /// Checks if the file has opened correctly
    if (!file) {
        cout << "File not found!\n";
        exit(0);
    }
    else {
        /// Setting the pointer to the end of the file
        file.seekg(0L, ios::end);

        /// Get the whole file byte size.
        auto pos = file.tellg();

        /*!
         * Calculate the needed size of the array.
         *
         * How? We have the file byte size and our struct
         *      represents just one item from our array.
         *      To get our array size, we need to divide
         *      the byte size of the file, where we stored
         *      the array of Player, and the size in bytes
         *      of our struct Player, thus: sizeof(Player).
         *
         * \see Player
         */
        auto array_size = pos / sizeof(Player);

        /// Getting back to the beginning of the file to read it
        file.seekg(0L, ios::beg);

        /*!
         * Reading the whole file, because we have array_size * sizeof(Player),
         *      as a constant string(char *), and writing it by its' places in the struct.
         *      - id from the file goes to id from the struct
         *      - first_name from the file goes to first_name from the struct
         *      - etc...
         *
         * \see Player
         */
        file.read((char *)array, array_size * sizeof(Player));

        do {

            /*!
             * Inputting what country we want to search for.
             *
             * \see getline
             * \see std::string
             */
            cout << "Enter country you want to search for: ";
            getline(cin, country);

            /// Iterating through the array
            for (size_t i = 0; i < array_size; i++) {
                /// Check if each element's country is equal to what we inputted
                if (array[i].country == country) {
                    cout << "ID: " << array[i].id << endl;
                    cout << "First Name: " << array[i].first_name << endl;
                    cout << "Last Name: " << array[i].last_name << endl;
                    cout << "Country: " << array[i].country << endl;
                    cout << "Goals scored: " << array[i].scored_goals << endl;

                    /// Counter used for information only
                    counter++;
                }

                cout << "\n\n----------------------------------------------\n\n";
            }

            /// Counter used for information only
            if (counter == 0) {
                cout << "No players with this country found!\n\n";
            }

            /*!
             * Asking the user if he wants to query another country.
             *
             * \see _getch()
             * \see char
             */
            cout << "Do you want to search for another country? (y/n) ";
            choice = _getch();

            /*!
             * While the user enters anything different than the character n
             *      do this whole thing with the asking and printing.
             */
        } while (choice != 'n');
    }

    /// Closing the opened file
    file.close();
}

auto ModifyData(Player* array) -> void {

    string last_name, country;

    size_t counter(0);

    cout << "Enter Country you want to search for: ";
    cin >> country;

    cout << "Enter Last Name you want to search for: ";
    cin >> last_name;

    ifstream file("players.dat", ios::binary | ios::in);

    if (!file) {
        cout << "File not found!\n";
        exit(0);
    }
    else {
        file.seekg(0L, ios::end);

        auto pos = file.tellg();
        auto array_size = pos / sizeof(Player);

        file.seekg(0L, ios::beg);

        file.read((char *)array, array_size * sizeof(Player));

        for (size_t i = 0; i < array_size; i++) {
            if (array[i].country == country && array[i].last_name == last_name) {
                size_t goals_scored;

                cout << "ID: " << array[i].id << endl;
                cout << "First Name: " << array[i].first_name << endl;
                cout << "Last Name: " << array[i].last_name << endl;
                cout << "Country: " << array[i].country << endl;
                cout << "Goals scored: " << array[i].scored_goals << endl;

                cout << "\n\n";

                cout << "Modifying goals scored...\n\n";

                do {
                    cout << "Enter goals scored: ";
                    cin >> goals_scored;
                } while (goals_scored < 0);

                /// Modifying the value
                array[i].scored_goals = goals_scored;

                cout << "\n\nModified values:\n\n";

                cout << "ID: " << array[i].id << endl;
                cout << "First Name: " << array[i].first_name << endl;
                cout << "Last Name: " << array[i].last_name << endl;
                cout << "Country: " << array[i].country << endl;
                cout << "Goals scored: " << array[i].scored_goals << endl;
                counter++;
            }

            cout << "\n\n----------------------------------------------\n\n";
        }

        if (counter == 0) {
            cout << "No players with this combination of country and last name found!\n\n";
            file.close();
        }
        else {
            file.close();

            cout << "\n\nModifying file...\n\n";

            /// Modifying the file with the new modified structure
            fstream file("players.dat", ios::binary | ios::out);

            file.write((char *)array, array_size * sizeof(Player));

            file.close();
        }
    }
}