無法從數組中打印信息時，無法找出如何遍歷存儲在類中的數組？

Question

主要功能和類定義。 #include #include

using namespace std;

class gameobject
{
    public:
        void set_id_num(int num);
        int get_id_num();
        void set_name(string name1);
        string get_name();
        void set_type(int type_of_game);
        string get_type();
        void set_buy_value(float buy_game);
        float get_buy_value();
        void set_market_value(float market_price);
        float get_market_value();
        void set_year(int year1);
        int get_year();

    private:
        int id_num;//identifier number for the game
        string name;//the name of the game
        int type;//whether the game is cartridge, CD, DVD, BR, download
        string type_name;//type of game
        float buy_value;//price of game
        float market_value;//value of game
        int year;//year the game was made
};

class gamelist
{
private:
    int gamecounter = 0;
    gameobject gameobjects[10];

public:
    void add_game();
    void print_list();
    float total_value();
};

int main()
{
    int option;//menu choice

    do
    {
        //menu
        cout << endl;
        cout << "Please choose an option from the below menu. " << endl;
        cout << "1. Add Game" << endl;
        cout << "2. Print List" << endl;
        cout << "3. Total value of collection" << endl;
        cout << "4. Delete Game" << endl;
        cout << "5. Exit" << endl;
        cout << "Which would you like to execute? ";
        cin >> option;
        cin.ignore();

        //to add the games
        if (option == 1)
        {
            gamelist run;

            run.add_game();//goes through the options for setting up a game
        }

        //print game info
        else if (option == 2)
        {
            gamelist run;

            run.print_list();
        }

        //total value
        else if (option == 3)
        {
            gamelist run;

            run.total_value();
        }

    } while (option != 5);

    if (option == 5)
        return 0;
}

我遇到問題的區域。

//adds the inputted market value in the array
float gamelist::total_value()
{
    float value_of_games = 0;

    cout << "The value of the games is: ";

    for (int i = 0; i < gamecounter; i++)
    {
        value_of_games = gameobjects[i].get_market_value() + value_of_games;
    }

    return(value_of_games);
}
//prints the info in the array
void gamelist::print_list()
{
    cout << "The game information is listed below: " << endl;

    for (int i = 0; i < gamecounter; i++)
    {
        cout << gameobjects[i].get_id_num() << endl;
        cout << gameobjects[i].get_name() << endl;
        cout << gameobjects[i].get_type() << endl;
        cout << gameobjects[i].get_buy_value() << endl;
        cout << gameobjects[i].get_market_value() << endl;
        cout << gameobjects[i].get_year() << endl;
    }
}
//to add a game to the lise
void gamelist::add_game()
{
    gamecounter++;

    if (gamecounter > 10)
    {
        cout << "You cannot add any more games. ";
    }

    else
    {
        int id;
        string name_game;
        int type_game;
        int buy;
        int market;
        int year_game;

        cout << "Please enter an id number for the game: ";
        cin >> id;

        cout << "Please enter a name for the game: ";
        cin.ignore();
        getline(cin, name_game);

        cout << "There are four types of games." << endl;
        cout << "     0. Cartridge " << endl;
        cout << "     1. CD " << endl;
        cout << "     2. DVD " << endl;
        cout << "     3. BR " << endl;
        cout << "     4. Download " << endl;

        cout << "Which type do you want to set for the game (enter number)? ";
        cin >> type_game;

        cout << "Please set a buying value for the game: ";
        cin >> buy;

        cout << "Please set the market value of the game: ";
        cin >> market;

        cout << "What is the model year of the game? ";
        cin >> year_game;


        for (; gamecounter < 10; gamecounter++)
        {
            gameobjects[gamecounter].set_id_num(id);//passes value
            gameobjects[gamecounter].set_id_num(id);//passes value
            gameobjects[gamecounter].set_name(name_game);//passes value
            gameobjects[gamecounter].set_type(type_game);//passes value
            gameobjects[gamecounter].set_buy_value(buy);//passes value
            gameobjects[gamecounter].set_market_value(market);//passes value
            gameobjects[gamecounter].set_year(year_game);//passes value
        }
    }
}

設置和獲取功能。

//sets id num for the game
void gameobject::set_id_num(int num)
{
    id_num = num;
}

//displays the id num for the game
int gameobject::get_id_num()
{
    return(id_num);
}

//sets desired name for game
void gameobject::set_name(string name1)
{
    name = name1;
}

//displays the name of the game
string gameobject::get_name()
{
    return(name);
}

//presents a menu to choose type of game
void gameobject::set_type(int type_of_game)
{
    type = type_of_game;
}

//prints the type of game chosen
string gameobject::get_type()
{
    if (type == 0)
    {
        type_name = "cartridge";
        return(type_name);
    }
    else if (type == 1)
    {
        type_name = "CD";
        return(type_name);
    }
    else if (type == 2)
    {
        type_name = "DVD";
        return(type_name);
    }
    else if (type == 3)
    {
        type_name = "BR";
        return(type_name);
    }
    else if (type == 4)
    {
        type_name = "download";
        return(type_name);
    }
}

//sets the buying value of game
void gameobject::set_buy_value(float buy_game)
{
    buy_value = buy_game;
}

//displays the buying value for game
float gameobject::get_buy_value()
{
    return(buy_value);
}

//sets market value
void gameobject::set_market_value(float market_price)
{
    market_value = market_price;
}

//displays market value
float gameobject::get_market_value()
{
    return(market_value);
}

//sets model year of the game
void gameobject::set_year(int year1)
{
    year = year1;
}

//displays model year
int gameobject::get_year()
{
    return(year);
}

我的問題是，我如何計算增加的​​游戲數量？ 因為我的操作方式不起作用。

如何更改打印功能，使其實際打印出一些東西？ 我的代碼沒有寫在那里，但是經過一番研究，我真的不知道為什么它不起作用。

最后，我完全不贊成將每個游戲的市場價值相加以獲得總價值。 這是total_value函數。 我嘗試了一下，但是那里也有一些錯誤。

提前致謝！！

Answer 1

C ++數組從0開始當您添加它需要去位於索引0，這意味着你必須增加第一場比賽索引gamecounter你進入游戲的細節進入游戲后陣。

可以將gamecounter視為兩件事：

1. 現在陣列中的游戲數

2. 下一個游戲將去的索引（而不是數組中最后一個游戲的索引）

如果您以這種方式工作，那么gamecounter將正確顯示游戲數。

當然，我不會是第一個告訴您使用std :: vector來存儲游戲的人。 那么您可以執行以下操作：

添加游戲：

gameobject go(...parameters...);
go.set...();
gameobjects.push_back(std::move(go)); 

獲得游戲數：

return gameobjects.size();

迭代所有游戲：

for(const auto& game : gameobjects) {
  // do what you need to do on game
}

Answer 2

1）您需要不在本地（每次在if (option == ...)范圍內）聲明gamelist對象，而是在全局范圍內聲明：例如，在main標頭之后：

int main() {
    //declare you gamelist object here
    gamelist run;
    ...
}

這樣， gamelist對象將在用戶輸入之間保留並存儲信息。

2） addGame()應該只添加一個游戲，並且不需要循環線： for (; gamecounter < 10; gamecounter++)遞增計數器gamecounter++應該在addGame()函數的末尾進行。

Answer 3

使用vector來保存游戲對象，或者可以使用靜態成員變量來保存創建的游戲對象的數量。

對於矢量： http : //www.codeguru.com/cpp/cpp/cpp_mfc/stl/article.php/c4027/C-Tutorial-A-Beginners-Guide-to-stdvector-Part-1.htm

對於靜態成員： http : //www.learncpp.com/cpp-tutorial/811-static-member-variables/