C++ - 找不到运算符

Question

我有一个向量填充自定义类型的值,并且find()算法抱怨它无法为值比较找到合适的==运算符.我已经实现了这样:

bool Ship::operator==(const Ship& source) {
    return (_type == source._type &&
            _damagedSquares == source._damagedSquares &&
            _orientation == source._orientation && _state == source._state);
}

我也尝试了"朋友"方法,但这也不起作用.类本身的结构如下:

class Ship {
private:
    ShipType _type;
    int _damagedSquares;
    ShipOrientation _orientation;
    ShipState _state;

public:
    Ship();
    Ship(ShipType type);
    ~Ship();

    bool operator==(const Ship& source);
};

我在这做错了什么？

附加信息:

std::vector<Ship> remainingShips;
MultiArray& squares = opponentGridCopy.GetSquares();
for (RowIterator rowIterator = squares.begin(); rowIterator != squares.end();
     ++rowIterator) {
    for (ColumnIterator columnIterator = rowIterator->begin();
         columnIterator != rowIterator->end(); ++columnIterator) {
        Square* current = &(*columnIterator);
        SquareState currentState = current->GetState();
        if (currentState != SquareState::Hit)
            current->SetState(SquareState::Vacant);
        Ship* potentialShip = current->GetOwner();
        if (potentialShip != nullptr) {
            int damagedSquares = potentialShip->GetDamagedSquares();
            if (!damagedSquares) {
                current->SetState(SquareState::Populated);
                break;
            }
            if (remainingShips.empty() ||
                std::find(remainingShips.begin(), remainingShips.end(),
                          potentialShip) ==
                    remainingShips.end()) // should be *potentialShip
                remainingShips.push_back(*potentialShip);
        }
    }
}
return remainingShips;

我正在将指针作为比较值传递...只需取消引用它并且find()现在可以正常工作.

Answer 1

像这样声明你的比较运算符:

bool Ship::operator==( const Ship &source ) const

请注意尾随const.