C2236: unexpected 'class'

i have one header file Matrix4x4.h . it includes another header files. when i compile the code. it gives error "C2236: unexpected 'class' 'Matrix3x3'. Did you forget a ';'? " where i made mistake. how can i fix the problem. thanks in advance

Code:

---

#ifndef matrix4x4
#define matrix4x4

#include "Vector2D.h"
#include "Vector3D.h"
#include "Vector4D.h"
#include "Matrix3x3.h"

class Matrix3x3;    // compiler shows here error C2236

class Matrix4x4
{
public:
        ..................................
        ..................................
        Matrix4x4& operator=(const Matrix4x4& matrix1);
        Matrix4x4& operator=(const Matrix3x3& matrix1);
        friend Matrix4x4 operator-(const Matrix4x4& matrix1, const Matrix4x4& matrix2);
        friend Matrix4x4 operator+(const Matrix4x4& matrix1, const Matrix4x4& matrix2);
        friend Matrix4x4 operator*(const Matrix4x4& matrix1, const Matrix4x4& matrix2);
        friend Matrix4x4 operator*(const Matrix4x4& matrix1, const Matrix3x3& matrix2);
        friend Vector4D operator*(const Matrix4x4& matrix1, const Vector4D& v);
        friend Vector3D operator*(const Matrix4x4& matrix1, const Vector3D& v);
        friend Vector2D operator*(const Matrix4x4& matrix1, const Vector2D& v);
        friend Vector4D operator*(const Vector4D& v, const Matrix4x4& matrix1);
        friend Vector3D operator*(const Vector3D& v, const Matrix4x4& matrix1);
        friend Vector2D operator*(const Vector2D& v, const Matrix4x4& matrix1);
        friend Matrix4x4 operator*(float t, const Matrix4x4& matrix1);
        friend Matrix4x4 operator*(const Matrix4x4& matrix1, float t);
public:
        float m[16];
};

#endif

---

i fixed the problem. i forget putting semicolon end of the Matrix3x3 class. now code is working thanks have a nice evening

if you were including the header, what is the point in forward declaring it as well??

i read article says if there is 2 class like

//A.h
class A

and

//B.h
class B

if class B uses reference or pointers to A. use forward declaration. you dont need to include A.h. if B uses object of class A. you then need to include <A.h>
compiler shows error coming from class Matrix3x3 so i used forward declaration and includes to find out errors. the error arrises from semicolon end of the Matrix3x3 class.now i use forward declaration instead of includes.
thank you Amleto