我遇到了一个障碍，成员函数应该从文件中读取内容，并将内容逐行添加到Player对象数组中。最初我通过引用将testList2对象传递到成员函数中，代码工作正常，但是我被告知主文件不能被修改，并且readFile函数只能带一个参数。下面是来自测试文件的代码片段，以及前面提到的readFile成员函数。
我想弄清楚这一点，所以如果有人有一些一般性的建议，在没有给出答案的情况下为我指出正确的方向，我将非常感谢。

Contestants testList2;

    std::cout << "-----BEGIN FILE I/O TEST -----------\n\n";
    std::cout << "Test 1 - error opening file\n";
    std::cout << "\tEXPECTING: Could not open file.\n";
    std::cout << "\tACTUAL: ";
    testList2.readFile("testFil");
    
    std::cout << "\nTest 2 - append to object from file\n";
    testList2.readFile("testFile2"); // Function call here. Can not add second parameter.
    
    std::cout << "\nPrinting testList2 contents\n";
    for(int i = 0; i < testList2.getSize(); i++) {
        std::cout << "Player " << i + 1 << "\n";
        std::cout << testList2.at(i) << std::endl;
    }

bool Contestants::readFile(std::string fileName) {
    // Create object and open file
    Player tmpPlayer;
    std::ifstream inFile(fileName);

    // Check that file is open.
    if(!inFile) {
        std::cout << "Could not open file." << std::endl;
        return false;
    }
    std::cout << "File opened.\n" << std::endl;

    // Read the file line by line
    std::string line;
    std::string tmpName;
    std::string tmpScore;
    while(std::getline(inFile, line)) {
        //std::cout << line << std::endl; // This line is for testing purposes
        
        // Create a string stream read from input file.
        std::stringstream ss(line);
        // Store contents of the file into two seperate value delimited by a comma.
        if(std::getline(ss, tmpName, ',')) {
            if(std::getline(ss, tmpScore)) {
                tmpPlayer = Player(tmpName, stoi(tmpScore));
                testList2.append(tmpPlayer); // HOW TO APPEND TO CONTESTANTS OBJECT WITHOUT A SECOND FUNCTION PARAMETER?
            }
        }
    }
    
    // Check for errors or end of file
    if (inFile.bad()) {
        std::cout << "Error reading file." << std::endl;
        return false;
    } else if (inFile.eof()) {
        std::cout << "\nEnd of file reached." << std::endl;
    }
    
    // Close the file.
    inFile.close();
    std::cout << "\nFile closed." << std::endl;
    return true;
}

class Contestants
{

    public:
        // Static constant size maximum for array size.
        static const int MAX_SIZE = 3;

        // Default constructor
        Contestants();
    
    
        // Capacity
        int getSize()    const;  // Returns the number of objects held within Contestants
        int getMaxSize() const;  // Returns the value of MAX_SIZE
        bool isEmpty()   const; // Checks for empty object array.
        
        // Accessors
        int contains(const Player& player) const;  // Determines if Contestants contains specified Player object
        const Player& at(int index) const;        // Returns player object found at index param
        const Player& operator[](int index) const; // TODO
        
        // Modifiers
        void clearAll();                       // Resets object array to 0.
        bool append(const Player& player);      // Adds player objects and increases size.
        bool removePlayer(const Player& player); // Finds player object and calls removeByIndex()
        bool removeByIndex(int index);          // removes specified player object

        // Other (file IO)
        bool readFile(std::string fileName);  // TODO
        bool writeFile(std::string fileName); // TODO
    
    
    
    private:
        Player data[MAX_SIZE];
        int size;

};

我尝试过各种指针方法，但都抛出错误。