ASCII Character Set

Computers can only store numbers. Humans need words to communicate, so how can we make that happen? We can assign a numeric code to each letter we wish to represent. That leads to the questions: who assigned the numbers and what letters should be included?

In the beginning, the were no answers, and anyone could make up the answers they wanted to use. The manufacturers of equipment got together to figure out how to have one ansigure out how to have one answer for everyone, resulting in the American Standard Code for Information Interchange (ASCII). This resulted in 128 possible characters (using seven bits with one more to be used to facilitate communications).

Normally, values zero through thirty-one are non-printable characters. So is the value 127. The space character has the value of 32.

One of the tricks of the trade is that the character '0' is not the value 0. But since the numbers run consequentively, you can get the binary value of a character by subtracted the value of the character '0'. Thus, '9' - '0' = 9.

Another trick is that you can convert a lowercase letter to a uppercase letter by subtraction and addition:

'j' - 'a' + 'A'

The ASCII Chart

DEC	HEX	CHAR	DEC	HEX	CHAR	DEC	HEX	CHAR	DEC	HEX	CHAR
0	00	^@ NUL \0	32	20	SPC	64	40	@	96	60	'
1	01	^A SOH	33	21	!	65	41	A	97	61	a
2	02	^B STX	34	22	"	66	42	B	98	62	b
3	03	^C ETX	35	23	#	67	43	C	99	63	c
4	04	^D EOT	36	24	$	68	44	D	100	64	d
5	05	^E ENQ	37	25	%	69	45	E	101	65	e
6	06	^F ACK	38	26	&	70	46	F	102	66	f
7	07	^G BEL \a	39	27	'	71	47	G	103	67	g
8	08	^H BS \b	40	28	(	72	48	H	104	68	h
9	09	^I HT \t	41	29	)	73	49	I	105	69	i
10	0A	^J LF \n	42	2A	*	74	4A	J	106	6A	j
11	0B	^K VT \v	43	2B	+	75	4B	K	107	6B	k
12	0C	^L FF \f	44	2C	,	76	4C	L	108	6C	l
13	0D	^M CR \r	45	2D	-	77	4D	M	109	6D	m
14	0E	^N SO	46	2E	.	78	4E	N	110	6E	n
15	0F	^O SI	47	2F	/	79	4F	O	111	6F	o
16	10	^P DLE	48	30	0	80	50	P	112	70	p
17	11	^Q DC1	49	31	1	81	51	Q	113	71	q
18	12	^R DC2	50	32	2	82	52	R	114	72	r
19	13	^S DC3	51	33	3	83	53	S	115	73	s
20	14	^T DC4	52	34	4	84	54	T	116	74	t
21	15	^U NAK	53	35	5	85	55	U	117	75	u
22	16	^V SYN	54	36	6	86	56	V	118	76	v
23	17	^W ETS	55	37	7	87	57	W	119	77	w
24	18	^X CAN	56	38	8	88	58	X	120	78	x
25	19	^Y EM	57	39	9	89	59	Y	121	79	y
26	1A	^Z SUB	58	3A	:	90	5A	Z	122	7A	z
27	1B	^[ ESC	59	3B	;	91	5B	[	123	7B	{
28	1C	^\ FS	60	3C	<	92	5C	\	124	7C	\|
29	1D	^] GS	61	3D	=	93	5D	]	125	7D	}
30	1E	^^ RS	62	3E	>	94	5E	^	126	7E	~
31	1F	^_ US	63	3F	?	95	5F	_	127	7F	DEL