An ASCII (American Standard Code for Information Interchange) code represents each character (letters, digits, punctuation, control characters) as a unique numeric code. The ASCII table has 128 characters, numbered from 0 to 127, and each character has a corresponding decimal, hexadecimal, and binary representation.

Here is a comparison table for ASCII codes, showing decimal, hexadecimal, and binary values for common characters:

Character Decimal Hexadecimal Binary
Null (NUL) 0 0x00 00000000
Start of Heading (SOH) 1 0x01 00000001
Start of Text (STX) 2 0x02 00000010
End of Text (ETX) 3 0x03 00000011
End of Transmission (EOT) 4 0x04 00000100
Enquiry (ENQ) 5 0x05 00000101
Acknowledge (ACK) 6 0x06 00000110
Bell (BEL) 7 0x07 00000111
Backspace (BS) 8 0x08 00001000
Tab (HT) 9 0x09 00001001
Line Feed (LF) 10 0x0A 00001010
Vertical Tab (VT) 11 0x0B 00001011
Form Feed (FF) 12 0x0C 00001100
Carriage Return (CR) 13 0x0D 00001101
Shift Out (SO) 14 0x0E 00001110
Shift In (SI) 15 0x0F 00001111
Space 32 0x20 00100000
Exclamation mark (!) 33 0x21 00100001
Quotation mark (") 34 0x22 00100010
Hash (#) 35 0x23 00100011
Dollar ($) 36 0x24 00100100
Percent (%) 37 0x25 00100101
Ampersand (&) 38 0x26 00100110
Single quote (') 39 0x27 00100111
Left parenthesis (() 40 0x28 00101000
Right parenthesis ()) 41 0x29 00101001
Asterisk (*) 42 0x2A 00101010
Plus (+) 43 0x2B 00101011
Comma (,) 44 0x2C 00101100
Minus (-) 45 0x2D 00101101
Period (.) 46 0x2E 00101110
Slash (/) 47 0x2F 00101111
Zero (0) 48 0x30 00110000
One (1) 49 0x31 00110001
Two (2) 50 0x32 00110010
Three (3) 51 0x33 00110011
Four (4) 52 0x34 00110100
Five (5) 53 0x35 00110101
Six (6) 54 0x36 00110110
Seven (7) 55 0x37 00110111
Eight (8) 56 0x38 00111000
Nine (9) 57 0x39 00111001
Colon (:) 58 0x3A 00111010
Semicolon (;) 59 0x3B 00111011
Less than (<) 60 0x3C 00111100
Equal (=) 61 0x3D 00111101
Greater than (>) 62 0x3E 00111110
Question mark (?) 63 0x3F 00111111
At symbol (@) 64 0x40 01000000
A (uppercase) 65 0x41 01000001
B (uppercase) 66 0x42 01000010
C (uppercase) 67 0x43 01000011
D (uppercase) 68 0x44 01000100
E (uppercase) 69 0x45 01000101
F (uppercase) 70 0x46 01000110
G (uppercase) 71 0x47 01000111
H (uppercase) 72 0x48 01001000
I (uppercase) 73 0x49 01001001
J (uppercase) 74 0x4A 01001010
K (uppercase) 75 0x4B 01001011
L (uppercase) 76 0x4C 01001100
M (uppercase) 77 0x4D 01001101
N (uppercase) 78 0x4E 01001110
O (uppercase) 79 0x4F 01001111
P (uppercase) 80 0x50 01010000
Q (uppercase) 81 0x51 01010001
R (uppercase) 82 0x52 01010010
S (uppercase) 83 0x53 01010011
T (uppercase) 84 0x54 01010100
U (uppercase) 85 0x55 01010101
V (uppercase) 86 0x56 01010110
W (uppercase) 87 0x57 01010111
X (uppercase) 88 0x58 01011000
Y (uppercase) 89 0x59 01011001
Z (uppercase) 90 0x5A 01011010
Left square bracket ([) 91 0x5B 01011011
Backslash () 92 0x5C 01011100
Right square bracket (]) 93 0x5D 01011101
Caret (^) 94 0x5E 01011110
**Underscore (_) 95 0x5F 01011111
Backtick (`) 96 0x60 01100000
a (lowercase) 97 0x61 01100001
b (lowercase) 98 0x62 01100010
c (lowercase) 99 0x63 01100011
d (lowercase) 100 0x64 01100100
e (lowercase) 101 0x65 01100101
f (lowercase) 102 0x66 01100110
g (lowercase) 103 0x67 01100111
h (lowercase) 104 0x68 01101000
i (lowercase) 105 0x69 01101001
j (lowercase) 106 0x6A 01101010
k (lowercase) 107 0x6B 01101011
l (lowercase) 108 0x6C 01101100
m (lowercase) 109 0x6D 01101101
n (lowercase) 110 0x6E 01101110
o (lowercase) 111 0x6F 01101111
p (lowercase) 112 0x70 01110000
q (lowercase) 113 0x71 01110001
r (lowercase) 114 0x72 01110010
s (lowercase) 115 0x73 01110011
t (lowercase) 116 0x74 01110100
u (lowercase) 117 0x75 01110101
v (lowercase) 118 0x76 01110110
w (lowercase) 119 0x77 01110111
x (lowercase) 120 0x78 01111000
y (lowercase) 121 0x79 01111001
z (lowercase) 122 0x7A 01111010
Left curly brace ({) 123 0x7B 01111011
**Vertical bar ( )** 124 0x7C
Right curly brace (}) 125 0x7D 01111101
Tilde (~) 126 0x7E 01111110
Delete (DEL) 127 0x7F 01111111
Notes:
Decimal: The standard base-10 number.
Hexadecimal: The base-16 representation.
Binary: The base-2 representation.
Control Characters (0-31 and 127) are non-printable characters used for controlling devices or for communication purposes (like line breaks, carriage returns, etc.).