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 Example of How to Use 1- and 2-Byte Return Codes from INKEY$ - Q45909
 
 The INKEY$ function returns a 1- or 2-byte string containing a
 character read from the standard input device. A null string is
 returned if no character is waiting there. A 1-character string
 contains the actual character read from the keyboard, while a
 2-character string indicates an extended code, the first character
 of which is hexadecimal 00.
 
 When two bytes are received from an extended key, the second character
 of the string is the scan code associated with the extended key. The
 chart in the version 4.50 QuickBASIC Advisor and Microsoft Advisor
 on-line Help system for BASIC Professional Development System (PDS)
 version 7.00 contains the scan code listing. The extended keys
 include the function keys, arrow keys, HOME, PGUP, END, PGDN, and
 SHIFT+TAB keys.
 
 More Information:
 
 The following program example demonstrates how to use the INKEY$
 function to return either a 1-byte character or 2-byte extended code.
 The length, ASCII representation, and the numeric representation for
 each key that is pressed are displayed. In addition, the arrow keys
 and the SHIFT+TAB key combination are trapped for 2-byte returns, and
 the ESC, TAB, and SPACEBAR are trapped for 1-byte returns.
 
 Code Example
 ------------
 
 ' To try this example in VBDOS.EXE:
 ' 1. From the File menu, choose New Project.
 ' 2. Copy the code example to the Code window.
 ' 3. Press F5 to run the program.
 
 ' SCAN CODES to be used with a 2-byte return code from INKEY$.
 CONST left = &H4B
 CONST right = &H4D
 CONST up = &H48
 CONST down = &H50
 CONST tabscan = 15
 
 ' ASCII CODES  to be used with a 1-byte return from INKEY$.
 CONST escape = 27
 CONST tabchar = 9
 CONST space = 32
 
 CLS
 DO UNTIL UCASE$(t$) = "Q"  ' PROGRAM ENDS WHEN 'Q' OR 'q' IS ENTERED.
  LOCATE 23, 35
  PRINT "Q to quit"
  t$ = INKEY$
  IF t$<>"" THEN
   LOCATE 10, 1
   length% = LEN(t$)
   PRINT "length "; length%
   PRINT "ASCII representation "; t$
   PRINT "numeric representation ";
   SELECT CASE length%
          CASE 2
            FOR i = 1 TO 2
              PRINT ASC(MID$(t$, i, 1)); " ";
            NEXT i
                  SELECT CASE ASC(RIGHT$(t$, 1))
                          CASE up
                           PRINT "up           "
                          CASE down
                           PRINT "down         "
                          CASE left
                           PRINT "left         "
                          CASE right
                           PRINT "right        "
                          CASE tabscan
                           PRINT "Shift tab"
                  END SELECT
          CASE 1
            PRINT ASC(t$);
            SELECT CASE ASC(LEFT$(t$, 1))
                  CASE escape
                    PRINT "escape       "
                  CASE tabchar
                    PRINT "tab character"
                  CASE space
                    PRINT "space        "
            END SELECT
          CASE ELSE
            PRINT "                    "
   END SELECT
  END IF
 LOOP
 END