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If some of the WM_KEYDOWN meassage have a repeat count areater than 1,the corresponding WM_CHAR meassage will have the same repeat count the ctrl key in combination  with a letter key generates ASCII control charactyers from 0x01(ctrl a)
through 0x1A(ctrl z)
serveral of these control code are also genrated  by the  key show in the following  table
 ket character code duplicated by ANSI c ecape

backspace 0x08                                          ctrl.H/b
tab 0x09                                                      ctrl.I/t  
ctrl. enter 0x0A                                          ctrl.I/n
enter 0x0d                     	           ctrl.M/v
ESC 0x1B                                                    ctrl.[ 

In this case ,the letter key are not translated into character messages

CONTROL  Character Processing
These are basic rule for processing Keystorkes and character message like this :
If wwe need to read keyboard character input in owr window , we process the WM_CHAR  message if we need to read the cursor keys , functiion keys , Delete  , Insert , Shift , Ctrl , & Alt we process the WM_KEYDOWN message 
                                                                    