ASCII: Difference between revisions

From QB64 Phoenix Edition Wiki

Latest revision as of 12:25, 19 November 2024

ASCII and Extended Codes

ASCII Control 0 to 31 \| ASCII Keyboard Character Codes 32 to 127
Code	Character `[key]`	Code	Character	Code	Character	Code	Character
0	(NUL)	32	[`Spacebar`]	64	`@`	96	`
1	☺ (SOH)	33	!	65	A	97	a
2	☻ (STX)	34	"	66	B	98	b
3	♥ (ETX)	35	#	67	C	99	c
4	♦ (EOT)	36	$	68	D	100	d
5	♣ (ENQ)	37	%	69	E	101	e
6	♠ (ACK)	38	&	70	F	102	f
7	• (BEL) `BEEP`	39	'	71	G	103	g
8	◘ [`BackSpace`] **	40	(	72	H	104	h
9	○ (HT) [`TAB`] **	41	)	73	I	105	i
10	◙ (LineFeed) **	42	*	74	J	106	j
11	♂ (VT) **	43	+	75	K	107	k
12	♀ (FormFeed) **	44	,	76	L	108	l
13	♪ (CR) [`Enter`] **	45	-	77	M	109	m
14	♫ (SO)	46	.	78	N	110	n
15	☼ (SI)	47	/	79	O	111	o
16	► (DLE)	48	0	80	P	112	p
17	◄ (DC1)	49	1	81	Q	113	q
18	↕ (DC2)	50	2	82	R	114	r
19	‼ (DC3)	51	3	83	S	115	s
20	¶ (DC4)	52	4	84	T	116	t
21	§ (NAK)	53	5	85	U	117	u
22	▬ (SYN)	54	6	86	V	118	v
23	↨ (ETB)	55	7	87	W	119	w
24	↑ (CAN)	56	8	88	X	120	x
25	↓ (EM)	57	9	89	Y	121	y
26	→ (SUB) `EOF`	58	:	90	Z	122	z
27	← (ESC) [`Esc`]	59	;	91	[	123	{
28	∟ (FS) **	60	<	92	\	124	\|
29	↔ (GS) **	61	=	93	]	125	}
30	▲ (RS) **	62	>	94	^	126	~
31	▼ (US) **	63	?	95	_	127	⌂ (DEL) *
IBM, International, graphical, mathematical and other characters
Code	Character	Code	Character	Code	Character	Code	Character
128	Ç	160	á	192	└	224	α
129	ü	161	í	193	┴	225	ß
130	é	162	ó	194	┬	226	Γ
131	â	163	ú	195	├	227	π
132	ä	164	ñ	196	─	228	Σ
133	à	165	Ñ	197	┼	229	σ
134	å	166	ª	198	╞	230	µ
135	ç	167	º	199	╟	231	τ
136	ê	168	¿	200	╚	232	Φ
137	ë	169	⌐	201	╔	233	Θ
138	è	170	¬	202	╩	234	Ω
139	ï	171	½	203	╦	235	δ
140	î	172	¼	204	╠	236	∞
141	ì	173	¡	205	═	237	φ
142	Ä	174	«	206	╬	238	ε
143	Å	175	»	207	╧	239	∩
144	É	176	░	208	╨	240	≡
145	æ	177	▒	209	╤	241	±
146	Æ	178	▓	210	╥	242	≥
147	ô	179	│	211	╙	243	≤
148	ö	180	┤	212	╘	244	⌠
149	ò	181	╡	213	╒	245	⌡
150	û	182	╢	214	╓	246	÷
151	ù	183	╖	215	╫	247	≈
152	ÿ	184	╕	216	╪	248	°
153	Ö	185	╣	217	┘	249	∙
154	Ü	186	║	218	┌	250	·
155	¢	187	╗	219	█	251	√
156	£	188	╝	220	▄	252	ⁿ
157	¥	189	╜	221	▌	253	²
158	₧	190	╛	222	▐	254	■
159	ƒ	191	┐	223	▀	255	NBSP ***

* DEL was used to erase paper tape data by punching out all of the 7 holes.

** Control characters 8 to 13 and 28 to 31 can move text formatting when printed and do not display

*** NBSP is a Non-breaking Space used to indent text. Some browsers may handle this character differently

More information about ASCII Control Characters

Unicode Character Table

Control Characters

INKEY$ will return Control + letter key press combinations as the equivalent control characters or bold function keys listed below:

 CTRL + A = CHR$(1)   ☺  StartHeader (SOH)    CTRL + B = CHR$(2)   ☻  StartText         (STX)
 CTRL + C = CHR$(3)   ♥  EndText     (ETX)    CTRL + D = CHR$(4)   ♦  EndOfTransmit     (EOT)
 CTRL + E = CHR$(5)   ♣  Enquiry     (ENQ)    CTRL + F = CHR$(6)   ♠  Acknowledge       (ACK)
 CTRL + G = CHR$(7)   •  Bell        (BEL)    CTRL + H = CHR$(8)   ◘  [Backspace]       (BSP)
 CTRL + I = CHR$(9)   ○  Horiz.Tab   [Tab]    CTRL + J = CHR$(10)  ◙  LineFeed(printer) (LF)
 CTRL + K = CHR$(11)  ♂  Vert. Tab   (VT)     CTRL + L = CHR$(12)  ♀  FormFeed(printer) (FF)
 CTRL + M = CHR$(13)  ♪  [Enter]     (CR)     CTRL + N = CHR$(14)  ♫  ShiftOut          (SO)
 CTRL + O = CHR$(15)  ☼  ShiftIn     (SI)     CTRL + P = CHR$(16)  ►  DataLinkEscape    (DLE)
 CTRL + Q = CHR$(17)  ◄  DevControl1 (DC1)    CTRL + R = CHR$(18)  ↕  DeviceControl2    (DC2)
 CTRL + S = CHR$(19)  ‼  DevControl3 (DC3)    CTRL + T = CHR$(20)  ¶  DeviceControl4    (DC4)
 CTRL + U = CHR$(21)  §  NegativeACK (NAK)    CTRL + V = CHR$(22)  ▬  Synchronous Idle  (SYN)
 CTRL + W = CHR$(23)  ↨  EndTXBlock  (ETB)    CTRL + X = CHR$(24)  ↑  Cancel            (CAN)
 CTRL + Y = CHR$(25)  ↓  EndMedium   (EM)     CTRL + Z = CHR$(26)  →  End Of File(SUB)  (EOF)

   Red symbols will format text and not PRINT the symbol. _PRINTSTRING can print in QB64

Control characters 1 to 26 can be used to simulate Ctrl + letter key shortcuts in Windows programs using _SCREENPRINT.
_CONTROLCHR OFF can also be used in QB64 to allow control characters to be printed without formatting the text.

ASCII in Text and Printing

Characters 0(NULL) and 255(NBSP) can also be used to print spaces(32). Useful for making file names harder to delete too.
Character 7 will create a BEEP sound when printed in QB64 or an error sound in QBasic using a SCREEN 0 window.
Character 8 is returned when the Backspace key is pressed.
Characters 9 thru 13 and 28 thru 31 can affect screen or file text placements and do not display the character when printed:

Character 9 will Tab space the cursor 8 column spaces when printed.
Character 10 moves the cursor or "line feeds" the printer head down one row.
Character 11 vertical tabs the cursor back to top left position of page or screen. Acts like CLS.
Character 12 acts like CLS when printed. "Form feeds" the page out of printers.
Character 13 is the cursor or typing "carriage return" to the start of the line on left side. Returned when Enter key pressed.
Character 28 designates a File Separator. Moves the print cursor one space right. Combination Ctrl + \
Character 29 designates a Group Separator. Moves the print cursor one space left. Combination Ctrl + ]
Character 30 designates a Record Separator. Moves the print cursor one row up. Combination Ctrl + ^
Character 31 designates a Unit Separator. Moves the print cursor one row down. Combination Ctrl + _

QB64 can display all of the control characters without formatting the text using _PRINTSTRING.
Characters 13 and 10 can be combined to create the CrLf carriage return used in files or printing. crlf$ = CHR$(13) + CHR$(10).
Character 16, the data link escape(DLE) character, can designate that a control character is being sent from a COM port.

Example: (DLE) <XON> <DATA PACKET> (DLE) <XOFF> or (DLE) <STX> <DATA PACKET> (DLE) <ETX>

Character 17, Device Control 1, is used with COM ports to mark the start of a transmission as "XON". The character is read.
Character 19, Device Control 3, is used with COM ports to mark the end of a transmission as "XOFF". The character is NOT read.
Character 26 can be used to designate the end of a file. See EOF.
Character 27 ← is returned when the Escape key is pressed.

Control character PRINT actions can be controlled using _CONTROLCHR OFF or ON in QB64.

SCREEN 12
COLOR 14: PRINT "Press Control + letter key combinations."
DO
    K$ = INKEY$
    IF LEN(K$) THEN
        code = ASC(K$)
        IF code < 32 THEN _PRINTSTRING (220, 100), "Ctrl + " + CHR$(code + 64) + " = " + K$ + " "
    END IF
LOOP UNTIL K$ = CHR$(27)

END

ASCII Character Usage

Characters are one byte and take up one space(byte) in a STRING value or variable.
Extended(non-keyboard) characters can be entered by holding down Alt key and entering the code number on the Number pad.
PRINTs text characters and symbols or formats the screen, printer or file.
BINARY files often store values below 256 in the one byte character. To read the value get the code with ASC.
Numerical values placed into a BINARY or RANDOM file using a GET or PUT variable, they will be stored in _MK$ format.
Characters 176 to 223 can be used to create screen borders or boundaries in an ASCII game. See: SCREEN (function)
Character 253(small 2) can be found as the first character byte of a BSAVEd image file opened in BINARY mode.
Character 255 can be used as the NBSP(non-breaking space) character on web pages to fill in extra spaces.
Can be used to crudely encrypt a file so others cannot read it by shifting the code values. See CHR$ example 2.

(Return to Table of Contents)

ASC Codes

ASC cannot read empty INKEY$ = "" loop reads! Check for them before reading ASC key press codes!

'                                ASCII Keyboard Codes
'
'  Esc  F1  F2  F3  F4  F5  F6  F7  F8  F9  F10  F11  F12  Sys ScL Pause
'   27 +59 +60 +61 +62 +63 +64 +65 +66 +67 +68  +133 +134   -   -    -
'  `~  1!  2@  3#  4$  5%  6^  7&  8*  9(  0) -_ =+ BkSp   Ins Hme PUp   NumL  /   *    -
'  126 33  64  35  36  37  94  38  42  40  41 95 43   8    +82 +71 +73    -    47  42   45
'   96 49  50  51  52  53  54  55  56  57  48 45 61
'  Tab Q   W   E   R   T   Y   U   I   O   P  [{  ]}  \|   Del End PDn   7Hme 8/▲  9PU  + 
'   9  81  87  69  82  84  89  85  73  79  80 123 125 124  +83 +79 +81   +71  +72  +73  43
'     113 119 101 114 116 121 117 105 111 112  91  93  92                 55   56   57 
'  CapL  A   S   D   F   G   H   J   K   L   ;:  '" Enter                4/◄-  5   6/-►
'    -   65  83  68  70  71  72  74  75  76  58  34  13                  +75  +76  +77  E
'        97 115 100 102 103 104 106 107 108  59  39                       52   53   54  n
'  Shift  Z   X   C   V   B   N   M   ,<  .>  /?    Shift       ▲        1End 2/▼  3PD  t
'    *    90  88  67  86  66  78  77  60  62  63      *        +72       +79  +80  +81  e
'        122 120  99 118  98 110 109  44  46  47                          49   50   51  r
'  Ctrl Win Alt       Spacebar          Alt Win Menu Ctrl   ◄-  ▼   -►   0Ins     .Del 
'   *    -   *           32              *   -   -    *    +75 +80 +77   +82       +83  13
'                                                                         48        46
'
'      Italics = LCase/NumLock On  ____________  + = 2 Byte: CHR$(0) + CHR$(code)

NOTE: The above commented table can be copied and pasted directly into the QB64 IDE

Use ASC(RIGHT$(key$, 1)) or ASC(key$, 2) in QB64 to read a two byte code when ASC(key$) = 0 * See the Two Byte Ctrl, Alt and Shift + Function key combinations below

'             Demo displays all ASCII codes and 2 byte code combinations
DO: K$ = INKEY$
    IF K$ <> "" THEN 'ASC will return an error if an empty string is read!
        IF ASC(K$) > 0 THEN
            PRINT "CHR$(" + LTRIM$(STR$(ASC(K$))) + ")" 'display normal keypress codes
        ELSE PRINT "CHR$(0) + CHR$(" + LTRIM$(STR$(ASC(K$, 2))) + ")" 'display 2 byte codes
        END IF
    END IF
LOOP UNTIL K$ = CHR$(27) 'escape key press exits

Note: In QB64 ASC(K$, 2) can read the second byte of the 2 byte code when ASC(K$) reads the first byte as 0.

(Return to Table of Contents)

Two Byte Codes

Two Byte ASCII Keyboard Return Values

INKEY$ returns both bytes when two byte keys or key combinations are pressed. The second byte = RIGHT$(keypress$, 1)
If the character returned is a two byte code, ASC will return 0. Warning: ASC cannot read empty INKEY$ string values!
In QB64 only, ASC(keypress$, 2) can return the second byte code. Don't read empty string values!
String values returned can be compared in an IF or SELECT CASE routine by using the actual string definitions such as:

IF INKEY$ = CHR$(0) + CHR$(80) THEN row = row + 1 or IF INKEY$ = CHR$(0) + "P" THEN row = row + 1

                 Two Byte Character Codes       Key                 CHR$(0) + "?" 

                    CHR$(0) + CHR$(16-50)      [Alt] + letter
                    CHR$(0) + CHR$(59)         [F1]                 ";"
                    CHR$(0) + CHR$(60)         [F2]                 "<"
                    CHR$(0) + CHR$(61)         [F3]                 "="
                    CHR$(0) + CHR$(62)         [F4]                 ">"
                    CHR$(0) + CHR$(63)         [F5]                 "?"
                    CHR$(0) + CHR$(64)         [F6]                 "@"
                    CHR$(0) + CHR$(65)         [F7]                 "A"
                    CHR$(0) + CHR$(66)         [F8]                 "B"
                    CHR$(0) + CHR$(67)         [F9]                 "C"
                    CHR$(0) + CHR$(68)         [F10]                "D"
                    CHR$(0) + CHR$(71)         [Home]               "G"
                    CHR$(0) + CHR$(72)         [↑] Up Arrow         "H"
                    CHR$(0) + CHR$(73)         [Page Up]            "I"
                    CHR$(0) + CHR$(75)         [←] Left Arrow       "K"
                    CHR$(0) + CHR$(76)         [5 NumberPad]        "L" (NumLock off in QB64)
                    CHR$(0) + CHR$(77)         [→] Right Arrow      "M"
                    CHR$(0) + CHR$(79)         [End]                "O"
                    CHR$(0) + CHR$(80)         [↓] Down Arrow       "P"
                    CHR$(0) + CHR$(81)         [Page Down]          "Q"
                    CHR$(0) + CHR$(82)         [Insert]             "R"
                    CHR$(0) + CHR$(83)         [Delete]             "S"
                    CHR$(0) + CHR$(84-93)      [Shift] + F1-10
                    CHR$(0) + CHR$(94-103)     [Ctrl] + F1-10
                    CHR$(0) + CHR$(104-113)    [Alt] + F1-10
                    CHR$(0) + CHR$(114-119)    [Ctrl] + keypad
                    CHR$(0) + CHR$(120-129)    [Alt] + number
                    CHR$(0) + CHR$(130 or 131) [Alt] + _/- or +/=   "é" or "â"
                    CHR$(0) + CHR$(133)        [F11]                "à"
                    CHR$(0) + CHR$(134)        [F12]                "å"
                    CHR$(0) + CHR$(135)        [Shift] + [F11]      "ç"
                    CHR$(0) + CHR$(136)        [Shift] + [F12]      "ê"
                    CHR$(0) + CHR$(137)        [Ctrl] + [F11]       "ë"
                    CHR$(0) + CHR$(138)        [Ctrl] + [F12]       "è"
                    CHR$(0) + CHR$(139)        [Alt] + [F11]        "ï"
                    CHR$(0) + CHR$(140)        [Alt] + [F12]        "î"

In QB64, CVI can be used to get the _KEYDOWN 2-byte code value. Example: status = _KEYDOWN(CVI(CHR$(0) + "P"))

See Scancodes for other keyboard function keys.

(Return to Table of Contents)

Examples

Example 1: Using arrow keys to move a text character. A change from a previous position tells program when to PRINT:

movey = 1: movex = 1 'text coordinates can never be 0
at$ = "@" 'text sprite could be almost any ASCII character
LOCATE movey, movex: PRINT at$;
DO
    px = movex: py = movey 'previous positions
    B$ = INKEY$
    IF B$ = CHR$(0) + CHR$(72) AND movey > 1 THEN movey = movey - 1 'rows 1 to 23 only
    IF B$ = CHR$(0) + CHR$(80) AND movey < 23 THEN movey = movey + 1
    IF B$ = CHR$(0) + CHR$(75) AND movex > 1 THEN movex = movex - 1 'columns 1 to 80 only
    IF B$ = CHR$(0) + CHR$(77) AND movex < 80 THEN movex = movex + 1

    IF px <> movex OR py <> movey THEN 'only changes when needed
        LOCATE py, px: PRINT SPACE$(1); 'erase old sprite
        LOCATE movey, movex: PRINT at$; 'show new position
    END IF
LOOP UNTIL B$ = CHR$(27) 'ESCape key exit
END

Example 2: Routine displays all keypress codes including Ctrl, Alt and Shift combinations. Ctrl + letter = control codes 1 to 26.

SCREEN 13
tmp$ = "   CHR$(###),\\,\          \       "
tmp2$ = "  CHR$(0) + CHR$(###) \           \"
COLOR 14: LOCATE 3, 3: PRINT "The code can tell what key is pressed"
COLOR 12: LOCATE 5, 14: PRINT CHR$(3); SPACE$(3);
COLOR 13: PRINT CHR$(5); SPACE$(3);
COLOR 12: PRINT CHR$(4); SPACE$(3);
COLOR 13: PRINT CHR$(6)
COLOR 10: LOCATE 7, 4: PRINT " Hit a key to find the ASCII Code"
COLOR 5: LOCATE 13, 1: PRINT " Codes below 33 are called control keys"
LOCATE 14, 1: PRINT " CHR$(0) + are 2 byte Extended key codes"
COLOR 13: LOCATE 16, 1: PRINT " Extended: Press Alt + numberpad: Enter"
LOCATE 18, 1: PRINT "  Try some Ctrl, Alt, or Shift Combo's"
COLOR 5: LOCATE 20, 1: PRINT " INKEY$ is used to detect the key entry"
COLOR 2: LOCATE 22, 15: PRINT CHR$(1); "       "; CHR$(2)
COLOR 4: LOCATE 24, 10: PRINT "To Quit hit the TAB key";

COLOR 9
DO
    DO: SLEEP: A$ = INKEY$: LOOP UNTIL A$ <> "" 'legal ASC read keys
    IF ASC(A$) > 0 THEN ' normal key codes
        code% = ASC(A$)
        SELECT CASE code%
            CASE 7: Key$ = "Beep"
            CASE 8: Key$ = "Backspace"
            CASE 9: Key$ = "Tab Key"
            CASE 10: Key$ = "Line Feed"
            CASE 12: Key$ = "Form Feed"
            CASE 13: Key$ = "Enter"
            CASE 27: Key$ = "Escape"
            CASE 32: Key$ = "Space Bar"
            CASE 48 TO 57: Key$ = "Number"
            CASE 65 TO 90: Key$ = "Uppercase"
            CASE 97 TO 122: Key$ = "Lowercase"
            CASE ELSE: Key$ = ""
        END SELECT
        SELECT CASE code% 'check for unprintable control combo characters
            CASE 10 TO 13: Kcode% = 32
            CASE ELSE: Kcode% = code%
        END SELECT
        COLOR 9: LOCATE 10, 5: PRINT USING tmp$; code%; CHR$(Kcode%); Key$;
    END IF
    IF ASC(A$) = 0 THEN 'two byte key codes
        code% = ASC(RIGHT$(A$, 1)) 'QBasic code
        'code% = ASC(A$, 2)        'QB64 code alternative
        SELECT CASE code%
            CASE 16 TO 50: Key$ = "Alt+ letter"
            CASE 72: Key$ = CHR$(24) + " Arrow"
            CASE 75: Key$ = CHR$(27) + " Arrow"
            CASE 77: Key$ = CHR$(26) + " Arrow"
            CASE 80: Key$ = CHR$(25) + " Arrow"
            CASE 83: Key$ = "Delete"
            CASE 59: Key$ = "F1"
            CASE 60: Key$ = "F2"
            CASE 61: Key$ = "F3"
            CASE 62: Key$ = "F4"
            CASE 63: Key$ = "F5"
            CASE 64: Key$ = "F6"
            CASE 65: Key$ = "F7"
            CASE 66: Key$ = "F8"
            CASE 67: Key$ = "F9"
            CASE 68: Key$ = "F10"
            CASE 71: Key$ = "Home"
            CASE 73: Key$ = "Page " + CHR$(24)
            CASE 79: Key$ = "End"
            CASE 81: Key$ = "Page " + CHR$(25)
            CASE 82: Key$ = "Insert"
            CASE 83: Key$ = "Delete"
            CASE 84 TO 93: Key$ = "Shift+ F"
            CASE 94 TO 103: Key$ = "Ctrl+ F"
            CASE 104 TO 113: Key$ = "Alt+ F"
            CASE 114 TO 119: Key$ = "Ctrl + pad"
            CASE 120 TO 129: Key$ = "Alt+ number"
            CASE 132: Key$ = "Ctrl + pad"
            CASE 133: Key$ = "F11"
            CASE 134: Key$ = "F12"
            CASE 135: Key$ = "Shift+ F11"
            CASE 136: Key$ = "Shift+ F12"
            CASE 137: Key$ = "Ctrl+ F11"
            CASE 138: Key$ = "Ctrl+ F12"
            CASE 139: Key$ = "Alt+ F11"
            CASE 140: Key$ = "Alt+ F12"
            CASE ELSE: Key$ = ""
        END SELECT
        LOCATE 10, 5: PRINT USING tmp2$; code%; Key$
    END IF
LOOP UNTIL A$ = CHR$(9)
SOUND 400, 4
SLEEP 3
SYSTEM

Code by Ted Weissgerber

Explanation: The routine checks for a keypress and SLEEP guarantees that ASC will never read an empty string from INKEY$. When the keypress is determined to be two bytes (ASC(A$) = 0) the second SELECT CASE routine is used. You can even display non-keyboard extended characters. Just press Alt + numberpad code, release and press enter.

Note: Ctrl + letter keys will list the contol keys as normal codes. EX: Ctrl + G will BEEP (CHR$(7)).

(Return to Table of Contents)

More Examples

Printable ASCII Table: _PRINTIMAGE (see Example 2 on page)

QB64 Programming References

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ASCII: Difference between revisions

Latest revision as of 12:25, 19 November 2024

Contents

ASCII and Extended Codes

Control Characters

ASC Codes

Two Byte Codes

Examples

More Examples

See also

QB64 Programming References

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ASCII: Difference between revisions

Latest revision as of 12:25, 19 November 2024

ASCII and Extended Codes

Control Characters

ASC Codes

Two Byte Codes

Examples

More Examples

See also

QB64 Programming References

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