没有匹配函数来调用类型＆const; constMap :: comp＆＃39;

Question

struct comp
{
    bool operator()(const CartesianLocation& loc1, const CartesianLocation& loc2)
    {
        //Compare the 2 locations, return true if loc1 is less than loc2
        return loc1.id < loc2.id;
    }
};

std::map<CartesianLocation, std::list<RadioSignal<RadioDevice>>, comp> radioMap;

public:
  void add(CartesianLocation location, std::list<RadioSignal<RadioDevice>> observedSignals) {
    radioMap[location] = observedSignals;
  }

在这一行radioMap[location] = observedSignals;我收到以下错误：

  

没有用于调用类型＆＃39; const RadioMap :: comp＆＃39;的对象的匹配函数在这一行if（__tree_.value_comp（）。key_comp（）（__ k，__ right-＆gt; __ value _.__ cc.first））

知道我哪里错了吗？

Answer 1

您在const的调用运算符上缺少comp限定符：

bool operator()(const CartesianLocation& loc1, 
                const CartesianLocation& loc2) const { }
                                               ^^^^^