The ASCII code table information is represented by binary on the computer, which is difficult to understand. Therefore, both input and output devices are provided, the main purpose of these devices is to display information on these devices in these devices in a human readable form. In order to ensure correct information exchange between humans and equipment, equipment, and computers, people have prepared a unified information exchange code, which is the ASCII code table, and its full name is "US Information Exchange Standard Code".
Octal, hexadecimal decimal octal hexadecimal characters Decimal characters 00000nul1004064 @ 01011soh1014165A02022stx1024266B03033etx1034367C04044eot1044468D05055enq1054569E06066ack1064670F07077bel1074771G10088bs1104872H11099ht1114973I120a10nl1124a74J130b11vt1134b75K140c12ff1144c76L150d13er1154d77M160e14so1164e78N170f15si1174f79O201016dle1205080P211117dc11215181Q221218dc21225282R231319dc31235383S241420dc41245484T251521nak1255585U261622syn1265686V271723etb1275787W301824can1305888X311925em1315989Y321a26sub1325a90Z331b27esc1335b91 [341c28fs1345c92 / 351d29gs1355d93] 361e30re1365e94 ^ 371f31us1375f95_402032sp1406096'412133! 1416197a422234 "1426298b432335 # 1436399c442436 $ 14464100d452537% 14565101e462638 & 14666102f472739`14767103g502840 (15068104h512941) 15169105i522a42 * 1526a106j532b43 1536b107k542c44,1546c108l552d45- 1556d109m562e46.1566e110n572f47 / 1576f111o603048016070112p613149116171113q623250216272114r633351316373115s643452416474116t653553516575117u663654616676118v673755716777119w703856817078120x713957917179121y723a58: 1727a122z733b59; 1737b123 {743c60 <174 7C124 | 753D61 = 1757d125} 763E62> 1767E126 ~ 773F63? 1777f127del
At present, the most widely used character set and its encoding are used in the computer, which is the AMERICAN Standard Code for Information Interchange, the US Standard Information Exchange Code, which has been International Standardization (ISO) ) Is set as an international standard, called ISO 646 standard. Suitable for all Latin letters, ASCII code has 7-digit code and 8-bit code.
........... Currently, the most widely used character set and its encoding are used in the computer, the AMERICAN Standard Code for Information Interchange, US Standard Information Exchange Code), it has been set by International Standardization Organization (ISO) as an international standard, called ISO 646 standard. Suitable for all Latin letters, ASCII code has 7-digit code and 8-bit code. Because the 1-bit binary number can be represented (21 =) 2 states: 0, 1; 2-bit binary number can be represented (22) = 4 states: 00, 01, 10, 11; secondary push, 7-bit binary number Indicates (27 =) 128 states, each state uniquely compiled a 7-bit binary code, corresponding to a character (or control code), which can be arranged into a decimal number 0 to 127. Therefore, the 7-bit ASCII code is encoded with seven-bit binary, and 128 characters can be represented.
第 0 to 32 and 127 (34) are control characters or communication-specific characters, such as controls: LF (wrap), CR (Enter), FF (change page), Del (delete), BS Randide, Bel (ring), etc .; communication dedicated characters: SOH (Wen Head), EOT (Site), ACK (confirmation), etc .;
No. 33-26 (a total of 94) are characters, including 0 ~ 90 Arabic numbers 48 ~ 90; 65 ~ 90 is 26 uppercase English letters, 97 ~ 122 is 26 lowercase English letters, The rest is some punctuation, the operation symbol, etc.
Note: In the memory cell of the computer, an ASCII code value accounts for one byte (8 binary bits), and its highest position (B7) is used as a parity bit. The so-called parity refers to a method for verifying whether there is an error in the code transfer process, generally derived by two types. Odd-calibration: The correct code 1 by one byte must be an odd number, if not odd, then add 1 in the highest bit B7; Even Value Specification: The correct code 1 number 1 must be an even number If non-even numbers, add 1 at the highest bit B7.
