Hi Thanks for the advice. Now, I created a new dialog class and i wanna use CDoc variable. AfxGetMainWnd doesnt work. I have tried GetActiveDocument and GetActiveFrame but it is for MainFrm. THanks.

Thx Astham There are 3 kinds of member variables/functions: public: Can be used/called by objects of any class private: Can be used by objects of this class only protected: Can be used by objects of this class and derived classes only. So if you want to use the variable from somewhere else than a CProgView member function, you need to make the variable public. If you use Add Member Variable there's three radio buttons at the bottom of the dialog. Or you could just write public: at the line before the variable declaration. THis is my header code, // Implementation public: float pointX[100]; float pointY[100]; virtual ~CMyProgView(); #ifdef _DEBUG virtual void AssertValid() const; virtual void Dump(CDumpContext& dc) const; #endif ] This is my public variable declaration. Why cant I use it? How to use it from my CMyProgDoc? I have #include CMyProgView.h and use it such as below: CMyProgView obView; obView.pointX[i] = something;

I think you need to declare the count variable outside this function, eg. declare it as global or class member variable. If you declare in this function, every time you click the mouse, the counter is reset to zero.

Hi thanks Do you mean outside the class or outside the onmouseover? It is actually outside the onmouseover and inside the class. Do you mean declaring as public variable? What kind of type of variable shld I use? CArray ? The VC++ doesnt allow me the declare this type. Someone in the forum mentioned to create another header file and include it before declaring it. I got a lot of errors after I did that.

Cant solve the CDoc error.

jw81 wrote: I can use for such case (linked list)? Look for Collection Classes in MSDN. Some of them are Clist CPtrArray CArray or In STL std::list std::vector "I Think this Will Help"  Alok Gupta  visit me at http://www.thisisalok.tk

You have declared a public varibale in one class,that means you can access that varable outide the class,but only through its member varible. jw81 wrote: why I can use other variables but not this? I didn't ge exaclty what you mean... But you can direclty use a varible if it is the same class' member varible.

See question 2.5[^] in the FAQ. --Mike-- Personal stuff:: Ericahist | Homepage Shareware stuff:: 1ClickPicGrabber | RightClick-Encrypt CP stuff:: CP SearchBar v2.0.2 | C++ Forum FAQ ----

Thanks K(arl), The program I need to write: 1st) User is required to draw a simple curve on the client. 2nd) The algorithm will scan the SDI client screen to find all the drawn coords on row/col basis. You have suggested to use CDC::GetPixel(). 3rd) Once a drawn pixel is found it will perform a 3x3 matrix check to determine the "connectivity" of this pixel. http://img52.exs.cx/img52/2303/3x3matrix.gif[^]If there are other drawn pixels in this 3x3 matrix, the drawn pixel is not an island. 4th) The program will keep scanning in loop to get to the end point of the curve. From there, the program will mark down a point for each specific distance of pixels. http://img40.exs.cx/img40/513/curve.gif[^] That is why I asked is there any function to check distance between endpoint to endpoint of a curve. My problem: 1) Is there a better way than my algorithm? Anyone has a better idea to scan pls reply here. My method is very tedious. THanks. 2) If there is an intersection such as the two curves intersection point. The program will be bugged (I foresee). Thanks a million

POINT p; GetClientRect(hwnd, &rcClip); p.x = rcClip.left; p.y = rcClip.top; ClientToScreen(hwnd, &p); OffsetRect(&rcClip, p.x, p.y); ClipCursor(&rcClip); ShowCursor(TRUE); ////////////////////////////// // The GetClientRect function retrieves the coordinates of a window's client area. The client coordinates specify the upper-left and lower-right corners of the client area. Because client coordinates are relative to the upper-left corner of a window's client area, the coordinates of the upper-left corner will be (0,0). // The ClientToScreen function replaces the client coordinates in the POINT structure with the screen coordinates. The screen coordinates are relative to the upper-left corner of the screen. // The OffsetRect function moves the specified rectangle by the specified offsets. // The ClipCursor function confines the cursor to a rectangular area on the screen. If a subsequent cursor position (set by the SetCursorPos function or the mouse) lies outside the rectangle, Windows automatically adjusts the position to keep the cursor inside the rectangular area.