Question

This is the dumbest little problem I am having and I CANNOT find the reason.

I am aware that there are dozens and dozens of this error already asked, but every one I read was about the order of declaration, however, I declare my struct before I use it in a function, and still get the error.

Here is the header file:

#ifndef GRAPH_H
#define GRAPH_H


#include <iostream>
#include <string>
using namespace std;

class Graph {

    public:
    struct Room;

    // destructor
    ~Graph();

    // copy constructor
    Graph(const Graph &v);

    // assignment operator
    Graph & operator = (const Graph &v);

    //Create an empty graph with a potential
    //size of num rooms.
    Graph( int num );

    //Input the form:
    //int -- numRooms times
    //(myNumber north east south west) -- numRooms times.
    void input(istream & s);

    //outputs the graph as a visual layout
    void output(ostream & s , string str );

    //Recursively searches for an exit path.
    void findPath( Room * start );

    //Moves room N E S or W
    void move( Room * room , string direction );

    //inputs the starting location.
    void inputStart( int start );

    //Searches the easyDelete array for the room with the
    //number "roomNumber" and returns a pointer to it.
    Room * findRoom( int roomNumber );

    struct Room
    {
        bool visited;
        int myNumber;

        Room *North;
        Room *East;
        Room *South;
        Room *West;
    };

    private:

    int numRooms;
    int _index;
    int _start;

    Room ** easyDelete;
    string * escapePath;

    Room * theWALL;
    Room * safety;
};

#endif

---

The specific error is: error: "Room" does not name a type, and it is talking about my

Room * findRoom( int roomNumber );

function, which is supposed to return a pointer to a "Room." I have tried putting the actual definition of the struct where the "struct Room;" is, to no avail.

Edit: My apologies, it’s in my .C file when I use it:

#include <iostream>
#include <string>
#include "Graph.h"
using namespace std;

...

Room * Graph::findRoom( int roomNumber )
{
    ...
}

Answer 1

are you sure the error is pointing to this .h file? there shouldn’t be this error…

if you write the implementation (in .cpp) like this

Room * Graph::findRoom( int roomNumber );

it should complain, because Room is a part of Graph:

Graph::Room * Graph::findRoom( int roomNumber );