Hi, In the book Programming for Windows by Charles Petzold I found code for drawing sinusoide using Polyline() function. However I need to draw a discrete sinusoide (I'm writing application that will simulate signal's sampling)
I manage to this making small changes

Code:
#include <windows.h>
#include <math.h>

#define NUM    200
#define TWOPI  (2 * 3.14159)

LRESULT CALLBACK WndProc (HWND, UINT, WPARAM, LPARAM) ;

int WINAPI WinMain (HINSTANCE hInstance, HINSTANCE hPrevInstance,
                    PSTR szCmdLine, int iCmdShow)
{
     static TCHAR szAppName[] = TEXT ("SineWave") ;
     HWND         hwnd ;
     MSG          msg ;
     WNDCLASS     wndclass ;
     
     wndclass.style         = CS_HREDRAW | CS_VREDRAW ;
     wndclass.lpfnWndProc   = WndProc ;
     wndclass.cbClsExtra    = 0 ;
     wndclass.cbWndExtra    = 0 ;
     wndclass.hInstance     = hInstance ;
     wndclass.hIcon         = LoadIcon (NULL, IDI_APPLICATION) ;
     wndclass.hCursor       = LoadCursor (NULL, IDC_ARROW) ;
     wndclass.hbrBackground = (HBRUSH) GetStockObject (WHITE_BRUSH) ;
     wndclass.lpszMenuName  = NULL ;
     wndclass.lpszClassName = szAppName ;
          
     if (!RegisterClass (&wndclass))
     {
          MessageBox (NULL, TEXT ("Program requires Windows NT!"), 
                      szAppName, MB_ICONERROR) ;
          return 0 ;
     }
     
     hwnd = CreateWindow (szAppName, TEXT ("Sine Wave Using Polyline"),
                          WS_OVERLAPPEDWINDOW,
                          CW_USEDEFAULT, CW_USEDEFAULT,
                          CW_USEDEFAULT, CW_USEDEFAULT,
                          NULL, NULL, hInstance, NULL) ;

     ShowWindow (hwnd, iCmdShow) ;
     UpdateWindow (hwnd) ;
     
     while (GetMessage (&msg, NULL, 0, 0))
     {
          TranslateMessage (&msg) ;
          DispatchMessage (&msg) ;
     }
     return msg.wParam ;
}

LRESULT CALLBACK WndProc (HWND hwnd, UINT message, WPARAM wParam, LPARAM lParam)
{
     static int  cxClient, cyClient ;
     HDC         hdc ;
     int         i ;
     PAINTSTRUCT ps ;
     POINT       apt [NUM] ;
     int k,p,X,Y;
     switch (message)
     {
     case WM_SIZE:
          cxClient = LOWORD (lParam) ;
          cyClient = HIWORD (lParam) ;
          return 0 ;
          
     case WM_PAINT:
		 
          hdc = BeginPaint (hwnd, &ps) ;
          
          MoveToEx (hdc, 0,        cyClient / 2, NULL) ;
          LineTo   (hdc, cxClient, cyClient / 2) ;
		  
		  
          for (i = 0 ; i < NUM ; i++)
          {
               apt[i].x = i * cxClient / NUM ;
               apt[i].y = (int) (cyClient / 2 * (1 - sin (TWOPI * i / NUM))) ;
			  
			   //My approach
			   
			   Y=apt[i].y;
			  
			   for(k=0;k<3;k++,Y++)
			   {
				  X=apt[i].x;
				  for(p=0;p<3;p++,X++)
					  SetPixel(hdc,X,Y,RGB(255,0,0));
			   }
			   
          }
          
          //Polyline (hdc, apt, NUM) ;
          return 0 ;
          
     case WM_DESTROY:
          PostQuitMessage (0) ;
          return 0 ;
     }
     return DefWindowProc (hwnd, message, wParam, lParam) ;
}
I was wondering if there any better method to draw point (it should be thicker then one pixel)!

Another thing I would like to ask is how much time did you spend lerning windows programming?
I didn't have any experience with windows programming before and when I started reading Petzold's book I found this is more harder then I expected because of so many system calls and a lot of functions! Maybe I should read some other book first before Petzolds?
Thanks for help!