Why am I getting “is not a class or namespace” err

Question

I have a file that is generating the error

"Block" is not a class or a namespace name

on the line

typedef Block::point point;

However, I'm positive that it's a class that I've both created and #included in the file below

'texture.h'.

    #pragma once
#include "Block.h"
#include <iostream>
#include <vector>
#include <GL/glut.h>
#include "lodepng.h"

using namespace std;
typedef Block::point point;


class Texture
{



public:
    Texture(int width, int height, string filename);//initialises our texture and loads its pixeldata into a buffer
    Texture(void);
    ~Texture(void);

    void draw(point centerPoint, point dimensions);

    unsigned int w;//width of our imagefile
    unsigned int h;

    GLuint texID;//the ID we will give OGL for this particular texture.

private:
    vector<unsigned char> image;
    void texGLInit();
};

Also just for good measure, here is the block.h file in question.

#pragma once
#include <GL/glut.h> 
#include <math.h>
#include <stdio.h>
#include <stdlib.h>
#include "Texture.h"

class Block
{


public:
    struct point
    {
        GLfloat x, y;
    };

    enum State  {STATIC, FALLING, SELECTED};

    enum Colour {RED, BLUE, PURPLE, GREEN, YELLOW, DEAD};

    Block(void);
    ~Block(void);

    Block(int gridPosX, int gridPosY, point offset);
    point gridPos;//the blocks designated position in the 8x8 array
    point centerPos;//the blocks coordinates for the actual purpose of drawing

    State blockState;//the state of the block
    Colour blockColour;//the colour of the block

    void move();//checks whether the block is in a falling state and moves it appropriately
    void drawBlock();//no need to include the drawing coords as parameters. the block knows where it should be. The grid will simply tell it to draw itself.

private:
    void fall();//decrements the blocks position
    void assignRandomColour();//assigns a random colour to the block dependant upon its' texture
    void generateWorldPos();//gets our block a center position, for us to later to use to draw it.
    //the above function will also inherently define the size of each cell in the grid. I'm thinking each
    //cell should be 40x40. So each cell will be offset initially by 20px by 20px. 



    point gridOffset;



};

I have no idea as to why i could be getting this error for a class that certainly exists. Thanks in advance.

Answer 1

I see cyclic includes : Block.h includes Texture.h which includes Block.h.

Search for "cyclic header dependency" on this site, you will see many topics on this, where you can find solution as to how to solve this puzzle, the most common being using forward declarations of classes and pointers declarations of member data. Forward declarations of classes helps you avoid including headers, and pointers declarations of data helps you defining the enclosing class. That is a just a hint, now search for aforementioned topics for detailed answers.