Currently, the most widely used character set and Its Encoding in computers are American Standard Code for information interchange (American Standard Code for information interchange) developed by the National Bureau of Standards (ANSI ), it has been set as an international standard by the International Organization for Standardization (ISO), known as the ISO 646 standard. It is applicable to all Latin characters, including 7-digit ASCII code and 8-digit ASCII code.
Because the number of one-bit binary data can be expressed as (21 =) two states: 0 and 1, while the number of two-bit binary data can be expressed as (22) = four states: 00, 01, 10, 11, and so on. A 7-bit binary number can represent (27 =) 128 States. Each State is uniquely encoded as a 7-bit binary code, corresponds to one character (or control code), which can be arranged into a decimal number ranging from 0 ~ 127. Therefore, the 7-bit ASCII code is encoded using the seven-bit binary number, which can represent 128 characters.
0th ~ 32 and 127th (34 in total) are control characters or communication special characters, such as control characters: LF (line feed), Cr (Press ENTER), FF (page feed), del (delete), BEL (zhenling); Communication special characters: Soh (Text header), EOT (Text tail), Ack (confirmation), etc;
33rd ~ 126 (94 in total) is a character, of which 48th ~ Number 57 is 0 ~ 9. 10 Arabic numerals; 65 ~ The 90 is 26 uppercase English letters, 97 ~ There are 26 lower-case English letters, and the remaining are some punctuation marks and operator numbers.
Note: In a computer's storage unit, an ascii code value occupies one byte (eight binary digits), and its highest bit (B7) is used as the parity bit. The so-called parity check refers to a method used to check whether an error occurs during code transfer. It is generally divided into two types: Odd checksum and even verification. Odd check rules: correct code must contain an odd number of 1 bytes. If the number is not an odd number, 1 is added to the highest bit B7. Even check rules: correct code: the number of 1 in a byte must be an even number. If the number is not an even number, 1 is added to the highest bit of B7.
For ease of query, the following table lists the ASCII code tables: Common ASCII code comparison tables.
128th ~ 255 is an extended character (not commonly used). If necessary, download the complete 8-bit ASCII two-dimensional table.
| ASCII code |
Keyboard |
ASCII code |
Keyboard |
ASCII code |
Keyboard |
ASCII code |
Keyboard |
| 27 |
ESC |
32 |
Space |
33 |
! |
34 |
" |
| 35 |
# |
36 |
$ |
37 |
% |
38 |
& |
| 39 |
' |
40 |
( |
41 |
) |
42 |
* |
| 43 |
+ |
44 |
' |
45 |
- |
46 |
. |
| 47 |
/ |
48 |
0 |
49 |
1 |
50 |
2 |
| 51 |
3 |
52 |
4 |
53 |
5 |
54 |
6 |
| 55 |
7 |
56 |
8 |
57 |
9 |
58 |
: |
| 59 |
; |
60 |
< |
61 |
= |
62 |
> |
| 63 |
? |
64 |
@ |
65 |
A |
66 |
B |
| 67 |
C |
68 |
D |
69 |
E |
70 |
F |
| 71 |
G |
72 |
H |
73 |
I |
74 |
J |
| 75 |
K |
76 |
L |
77 |
M |
78 |
N |
| 79 |
O |
80 |
P |
81 |
Q |
82 |
R |
| 83 |
S |
84 |
T |
85 |
U |
86 |
V |
| 87 |
W |
88 |
X |
89 |
Y |
90 |
Z |
| 91 |
[ |
92 |
/ |
93 |
] |
94 |
^ |
| 95 |
_ |
96 |
` |
97 |
A |
98 |
B |
| 99 |
C |
100 |
D |
101 |
E |
102 |
F |
| 103 |
G |
104 |
H |
105 |
I |
106 |
J |
| 107 |
K |
108 |
L |
109 |
M |
110 |
N |
| 111 |
O |
112 |
P |
113 |
Q |
114 |
R |
| 115 |
S |
116 |
T |
117 |
U |
118 |
V |
| 119 |
W |
120 |
X |
121 |
Y |
122 |
Z |
| 123 |
{ |
124 |
| |
125 |
} |
126 |
~ |
