在C ++中，如何將txt文件的不同行轉換為多個變量？

Question

我基本上是在嘗試創建簡單的文本冒險，保存文件中的每一行都將代表某個字符串或整數。

文本文件如下所示：

Tyler
Boy
1a
0

代碼如下：

 void open_file1() {
 struct file1 {
  std::string Name;
  std::string Gender;
  std::string Location;
  int Gold;

file1(std::string);
};
file1::file1(std::string"file1.txt") {
           std::ifstream Input("file1.txt".c_str());
              if (Input.is_open()) {
               std::getline(Input, this->Name);    //Reads first line into 'Name'
               std::getline(Input, this->Gender);  //Reads second line into 'Gender'
               std::getline(Input, this->Location); //Reads third line into   'Location'
    std:getline(Input, this->Gold); //Reads 4th line as 'Gold'
    cout << file1;
}
}
}

file1 :: file1（std :: string“ file1.txt”）{是我收到錯誤的位置...錯誤是這樣的：error：字符串常量之前的預期主表達式

我希望每一行代表一個單獨的變量。

因此， 泰勒將被分配給一個名為name的字符串。

男孩將被分配給一個名為性別的字符串，依此類推。到目前為止，我所能做的就是編寫代碼，或者在我的情況下將數據“保存”到一個文本文件中，直到玩家再次保存游戲后才可以對其進行修改。

Answer 1

看起來您可以從結構容器中受益。

假設：

struct Player
{
  std::string name;
  std::string gender;
  // other data
};

您可以實現std::vector<Player>來保存std::vector<Player>實例（或用您的術語說， 變量 ）。 這是程序員常用的技術。

Answer 2

正如托馬斯·馬修斯（Thomas Matthews）所說，最好將所有變量包裝在一個好的struct包中：

struct Player 
{
    std::string Name;
    std::string Gender;
    std::string Data;
    int OtherData;
};

至於從文件“加載”，您可以輕松創建一個構造函數以將數據加載到Player對象中：

#include <fstream> //So we can use std::ifstream

struct Player 
{
    std::string Name;
    std::string Gender;
    std::string Data;
    int OtherData;

    Player(std::string); //Our custom constructor
};

Player::Player(std::string fileName) {
    std::ifstream Input(fileName.c_str());
    if (Input.is_open()) {
        std::getline(Input, this->Name);    //Reads first line into 'Name'
        std::getline(Input, this->Gender);  //Reads second line into 'Gender'
        //etc...
    }
}

Answer 3

我可以為您提供一些指導，但距離完成還很遙遠。 您可以在錯誤處理，輸出格式設置，類設計等方面進行更多工作。

#include <fstream>
#include <iomanip>
#include <iostream>
#include <string>
#include <vector>

using namespace std;
using std::string;


// Player.h
class Player
{

public:
    // Constructors
    Player(string inName, string inGender, string inLocation, size_t inGold)
        : mName {inName}, mGender {inGender}
        , mLocation {inLocation}, mGold {inGold} {}
    // Default constructor
    Player()=default;
    // Copy constructor
    Player(const Player& player)
        : mName {player.mName}, mGender {player.mGender}
        , mLocation {player.mLocation}, mGold {player.mGold}  {}

   // This constructor is for demo only, move implementation to Player.cpp
   Player(const string& filename)
    {
        // Open the file and check for errors.
        ifstream inFile {filename.c_str()};
        if (!inFile) {
            throw invalid_argument("Unable to open file"); }
        // Read the names one at a time.
        for (Player player; inFile >> player; ) {
            // You can check that player is valid
            mName = player.mName;
            mGender = player.mGender;
            mLocation = player.mLocation;
            mGold = player.mGold;
        }

        inFile.close();
    }


private:
    string mName;
    string mGender;
    string mLocation;
    size_t mGold;

    friend std::ostream& operator<<(std::ostream& stream, const Player& player);
    friend std::istream& operator>>(std::istream& in, Player& player);
};

inline std::istream& operator>>(std::istream& in, Player& player)
{
    return in >> player.mName     >> player.mGender
              >> player.mLocation >> player.mGold;
}

inline std::ostream& operator<<(std::ostream& out, const Player& player)
{
    return out << std::setw(10) << player.mName << ' '
    << std::setw(10) << player.mGender  << ' '
    << std::setw(10) << player.mLocation << ' '
    << std::setw(10) << player.mGold << '\n';
}





// Test app

int main()
{

    Player player1 {"player1.txt"};
    cout << "Player 1: " << player1 << endl;
    return 0;
}