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28 lines
1.1 KiB
Markdown
28 lines
1.1 KiB
Markdown
---
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title: "ASCII"
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aliases:
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tags:
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- cosc204
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---
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# ASCII Character Code
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1. The computer uses ch as a integer index into a pre-existing table
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2. the computer screen is made up of a thousand little dots called pixels. theyre in a rectangular grid like a table.a
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- [ascii code example](https://i.imgur.com/9uvKRVo.png)
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- There are several tables that describe what to draw
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- fonts describe how to draw them
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- ASCII (american standard code for information) describes what should be drawn for Roman (english like) alphabets
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- e.g.,
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- A 1000001 (65)
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- B 1100001 (97)
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- 9 0111001 (57)
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- There are only a few letter numbers and punctuation marks. The remaining ASCII code are non-printing and have other meaning (line feed, for feed, tab etcc)
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- ASCII characters are stored using 7-bits
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- so there are 128 (2^7) possible characters
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- stored as a byte with the 8th bit set to zero
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- For sorting purposes characters are compared on their numeric value (called the *collating sequence*)
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- 'A' is before 'Z' but 'a' is after 'Z'! |