1/23/13 1 Computer Science CS101 Lecture 03: Hexadecimal Numbers Text Representation Hexadecimal Numbers Text Encoding ASCII and Unicode Aaron Stevens ([email protected]) 23 January 2013 Computer Science What You’ll Learn Today A great shortcut for writing binary numbers How do computers store text information?
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1/23/13
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Computer Science
CS101 Lecture 03: Hexadecimal Numbers Text Representation
Hexadecimal Numbers Text Encoding ASCII and Unicode Aaron Stevens ([email protected]) 23 January 2013
Computer Science
What You’ll Learn Today
A great shortcut for writing binary numbers How do computers store text information?
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Computer Science
Just Call Me!
Here’s my phone number: 000101101111111110010110010000011001!
What’s wrong with this number? !
– Hard to write on a napkin – Vulnerable to transcription errors – Won’t make you popular at parties
Computer Science
Binary, Hexadecimal, Decimal
Each four bits map to a hex digit. Hexadecimal prefix 0x????
No inherent value, just means “treat as a hex number”
Carnegie Mellon professor Scott E. Fahlman Proposed ASCII emoticons, Sept. 19, 1982. Source: http://www.wired.com/science/discoveries/news/2008/09/dayintech_0919
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Computer Science
Unicode Character Set
Extended ASCII is not enough for international use. Unicode uses 16 bits per character How many characters can UNICODE represent? Unicode is a superset of ASCII -- the first 256 characters
correspond exactly to the extended ASCII character set.
Computer Science Unicode Character Distribution
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Computer Science
Computer Science
What You Learned Today
More encoding!
Hexadecimal Numbers Character Sets ASCII Unicode
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Computer Science Announcements and To Do
Homework 1 due tonight! Readings:
Reed ch 5, pp 83-87, 89-90 (today)
Lab 2 on THURSDAY Go to your scheduled lab time. You must submit a document from the lab as evidence of