Characters Flashcards
What are alphanumeric characters?
- used to make words and strings
- include upper and lower case letters, digits and symbols
How can computers convert characters to binary code and vice versa?
Character sets
What are character sets?
Collections of characters that a computer recognises from their binary representation.
Character also contains what was well as alphanumerics?
Special characters which do certain commands like space, enter and delete.
How does the computer use character sets to translate the binary code into a particular character?
When you press a button on your keyboard it sends a binary signal to the computer telling it which key you pressed, then the computer translates it using character sets.
The number of bits you’ll need is based on what?
The character set
What is an example of a standard character set?
ASCII, extended ASCII and unicode
What is ASCII?
- most commonly used character set in the English speaking world
- each ASCII character is given a 7-bit binary code so can represent a total of 128 different characters.
- an extra 0 is added to the start of the binary code for each ASCII character, so each character can fit nicely into 1 byte.
What is extended ASCII?
- character set which gives each character an 8-bit binary code, so a total of 256 different characters can be represented.
- The first 128 are in the exact same order as ASCII
- particularly useful for european languages like French and German which include accents on some of their vowels.
What is unicode?
- comes in several different forms and tries to cover every possible character that might be written.
- most common forms is 16-bit and 32-bit binary codes.
- best thing is it covers all major languages even those who use a completely different alphabet like Greek, Russian and Chinese.
