Character Encoding Flashcards

1️⃣ Familiarise yourself with the flashcards:

  • Look through all the flashcards to see what's on both sides.
  • Make sure you understand the information on each card. If something's unclear, click the link to the revision notes at the bottom of the page for more details.

2️⃣ Test yourself:

  • Look at the question or prompt on each card and try to remember the answer before flipping it over.
  • Check the answer and make a note of any cards you find challenging and need to go over more.

3️⃣ Consistently Review and Practice:

  • Use spaced repetition: spend more time on the cards you struggle with and go over them more often.
  • Regularly review all the flashcards to help you better understand and retain the information over time.

Note: We may include questions that have multiple correct answers. It's useful to remember specific examples to understand these concepts better.

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What is character encoding?

It is a way to turn each character into a number so a computer can store and send it.

What is a character set?

It is the full list of characters and the codes used to represent them.

What does ASCII stand for?

American Standard Code for Information Interchange.

How many characters can 7-bit ASCII represent?

128 characters.

What is extended ASCII?

An 8-bit version of ASCII that can represent 256 characters.

Why can’t ASCII cover all world text?

It has too few codes, so many languages and emoji do not fit.

What is Unicode?

A standard that gives codes to characters from most languages and symbols, including emoji.

How is UTF-8 related to ASCII?

The first 128 UTF-8 codes match ASCII, so ASCII text is valid UTF-8.

What does variable-length mean in UTF-8?

Some characters use 1 byte, others use 2 to 4 bytes.

How do you work out a text file’s size from its character set?

Multiply the number of characters by bits per character, then divide by 8 to get bytes.

What happens if you open text with the wrong encoding?

You see wrong symbols or question marks instead of the real characters.

What is the rule linking bits per character to number of possible characters?

With b bits you can represent 2^b different characters. More bits means more characters.