#include <windows.h>





int checkbox_id = 156;


//prototype of window procedure


LRESULT WINAPI myProc(HWND hwnd, UINT message, WPARAM wParam, LPARAM lParam); 





int APIENTRY WinMain(HINSTANCE, HINSTANCE, LPSTR, int)


{


	MSG msg;


	HWND myDialog = CreateWindowEx(


		0,WC_DIALOG,"My Window",WS_OVERLAPPEDWINDOW | WS_VISIBLE,


		400,100,200,200,NULL,NULL,NULL,NULL


	);


	//create the checkbox


	HWND txt = CreateWindowEx(


		0,"BUTTON","Check and uncheck me",BS_AUTOCHECKBOX | WS_VISIBLE | WS_CHILD,


		10,50,170,25,myDialog,(HMENU)checkbox_id,NULL,NULL


	);


	


	SetWindowLong(myDialog, DWL_DLGPROC, (long)myProc);





	while(GetMessage(&msg,NULL,0,0)) { 


		TranslateMessage(&msg); 


		DispatchMessage(&msg);


	}





	return 0; 	


}





LRESULT WINAPI myProc(HWND hwnd, UINT message, WPARAM wParam, LPARAM lParam) 


{


	if(message == WM_CLOSE) 


		PostQuitMessage(0);		


		


	//check if checkbox was check or unchecked


	if(message==WM_COMMAND && LOWORD(wParam)==checkbox_id) 


	{


		//First get handle of checkbox by casting lParam to HWND


		HWND checkbox_handle = (HWND)lParam;


		//send message BM_GETCHECK to check box to retrieve its current state        


		int state = SendMessage(checkbox_handle,BM_GETCHECK,0,0);


		


		if(state == BST_CHECKED) //yes it is checked


			MessageBox(hwnd,"It hs checked","Message",0);


		else


			;//it has been Unchecked


	}


	


	return 0; 


}