Error: member function may not be declared outside of its class.

I have my heap.h file that contains:

bool insert(int key, double data);

and in my heapCPP.cpp file I have:

 bool heap::insert(int key, double data){
    bool returnTemp;
    node *temp = new node(key, data);

    returnTemp = insert(temp);
    delete temp;
    return returnTemp;
}

However, I get a error saying “member function “heap::insert” may not be redeclared outside its class.