Question

我正在尝试重载c ++运算符==但是我遇到了一些错误......

错误C2662：'CombatEvent :: getType'：无法将'this'指针从'const CombatEvent'转换为'CombatEvent＆amp;'

此错误在此行

if (lhs.getType() == rhs.getType())

见下面的代码：

class CombatEvent {

public:
    CombatEvent(void);
    ~CombatEvent(void);

    enum CombatEventType {
        AttackingType,
        ...
        LowResourcesType
    };

    CombatEventType getType();
    BaseAgent* getAgent();

    friend bool operator<(const CombatEvent& lhs, const CombatEvent& rhs) {

        if (lhs.getType() == rhs.getType())
            return true;

        return false;
    }

    friend bool operator==(const CombatEvent& lhs, const CombatEvent& rhs) {

        if (lhs.getType() == rhs.getType())
            return true;

        return false;
    }

private: 
    UnitType unitType;
}

任何人都可以帮忙吗？

Answer 1

CombatEventType getType();

需要

CombatEventType getType() const;

您的编译器正在抱怨，因为函数被赋予了const对象，您尝试将其调用为非const函数。当一个函数获得一个const对象时，在整个函数中对它的所有调用都必须是const（否则编译器无法确定它是否未被修改）。

Answer 2

将声明更改为：

CombatEventType getType() const;

你只能通过引用const来调用'const'成员。

Answer 3

这是一个const问题，你的getType方法没有被定义为const，但你的重载运算符参数是。因为getType方法不保证它不会更改类数据，所以编译器会抛出错误，因为您无法更改const参数;

最简单的更改是将getType方法更改为

CombatEventType getType() const;

除非该方法实际上是在改变对象。

Answer 4

我见过这样的错误代码

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当我更改为模板时，它起作用了。

    get_color(const std::unsigned_integral auto &x,
              const std::unsigned_integral auto &y,
              const BPPT &                       depth,
              const std::unsigned_integral auto &palette    = 0U,
              const std::unsigned_integral auto &texture_id = 0U) const

c ++错误C2662无法将'this'指针从'const Type'转换为'Type＆amp;'

4 个答案: