ASCII code-sequence code value comparison table

The value range of the ASCII code is 0 ~ 127, which can be expressed in 7 bits. C LanguagecharThe variable size is defined as one byte. If the ASCII code is stored, only seven characters are used, and the value is 0. The following is an ascii code table:

Figure A.1. ASCII code table

In most computers, one byte is 8 bits and the value range is 0 ~ 255, but the ASCII code is not specified as 128 ~ 255 characters. In order to express more characters, various manufacturers have developed many ASCII code extension specifications. Note that although these specifications are generally referred to as extended ASCII codes, they are not actually part of the ASCII code standard. For example, the following extended ASCII code is developed by IBM and widely used in character terminals. It contains many table edge characters used to draw interfaces.

Figure A.2. extended ASCII code table of IBM

The most widely used extended ASCII code in the graphic interface is ISO-8859-1, also known as Latin-1, which contains the most commonly used non-English letters in European languages, but after all only 128 characters, some letters in some languages are not included. See the following table.

Figure A.3. ISO-8859-1

ID: 128 ~ 159 is a number of control characters that are not listed in the preceding table.