没有匹配的函数来调用'const RadioMap :: comp'类型的对象

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;
  }

On this line radioMap[location] = observedSignals; I am getting below error:

No matching function for call to object of type 'const RadioMap::comp' on this line if (__tree_.value_comp().key_comp()(__k, __nd->__value_.__cc.first))

Any idea where I may be wrong?

Answer 1

You are missing the const qualifier on the call operator of comp :

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