    But the keyboard is also an input device that generates displayable characters or control 
characters.Every key can generate several different characters depending on the status 
of the ctrl,shift and caps lock keys.
     Normally if the caps key is off,the character typed is a lowercase.
     If ctrl is down,the character is a ctrl key which has meaning in ASCII but in windows 
is probably keyboard acceleration if anytheing
    One some keyboards, the keystorke might be preceded by a dead-character key or 
by shift,ctrl or alt in various combinitions.
    The combinitions could generate a lower case or uppercase letter with on accent
 mark,such as eg.a',a~,A~ or A'
     For keystrokes combinations that result in displayable characters,windows sends 
a program both keystorkes messages.
     Some keys do not generate characters these include the shift keys,the fuction 
keys,the cursor movement keys and special keys such as insert and delete.For these 
keys,windows generates onli keystrokes messages.