How text is stored (ASCII, Unicode) in Intro to Computing - Practice Exercises

Challenge - 5 Problems

🧠 Conceptual

intermediate

Understanding ASCII and Unicode

Which statement best explains the difference between ASCII and Unicode?

A ASCII and Unicode are exactly the same in how they store text.

B ASCII uses 7 bits per character and supports 128 characters, while Unicode uses multiple bytes to support over a million characters.

C Unicode is an older system that uses fewer bits than ASCII.

D ASCII supports all languages worldwide, but Unicode only supports English characters.

💡 Hint

Think about how many characters each system can represent.

ASCII is a 7-bit system supporting 128 characters mainly for English. Unicode uses more bits and can represent characters from many languages worldwide.

❓ trace

intermediate

Trace the Unicode encoding of a character

Given the character 'A', what is its Unicode code point and ASCII value?

A Unicode: U+0041, ASCII: 65

B Unicode: U+0061, ASCII: 97

C Unicode: U+0041, ASCII: 97

D Unicode: U+0061, ASCII: 65

💡 Hint

Remember 'A' uppercase has a different code than 'a' lowercase.

The uppercase 'A' has Unicode code point U+0041 and ASCII decimal value 65.

❓ Comparison

advanced

Comparing storage sizes of ASCII and Unicode

Which option correctly compares the storage size needed for the word 'Hello' in ASCII and Unicode UTF-8 encoding?

A 'Hello' uses 5 bytes in ASCII and 10 bytes in UTF-8 Unicode.

B 'Hello' uses 10 bytes in ASCII and 5 bytes in UTF-8 Unicode.

C 'Hello' uses 5 bytes in ASCII and 15 bytes in UTF-8 Unicode.

D 'Hello' uses 5 bytes in ASCII and 5 bytes in UTF-8 Unicode.

💡 Hint

Consider that ASCII characters are encoded the same way in UTF-8.

ASCII characters are encoded in one byte each. UTF-8 encodes ASCII characters using one byte as well, so 'Hello' uses 5 bytes in both.

❓ identification

advanced

Identify the error in Unicode representation

Which option shows an incorrect Unicode escape sequence for the character '€' (Euro sign)?

A '\u20AC'

B '\u0024'

C '\u20AG'

D '\u20ac'

💡 Hint

Unicode escape sequences use hexadecimal digits 0-9 and A-F only.

Option C contains 'G' which is not a valid hexadecimal digit, so it is an invalid Unicode escape sequence.

🚀 Application

expert

Determine the number of characters stored

A text file contains the string '你好' (two Chinese characters). How many bytes does it take to store this string in UTF-8 encoding?

A 6 bytes

B 4 bytes

C 2 bytes

D 8 bytes

💡 Hint

Each Chinese character typically uses 3 bytes in UTF-8.

Each Chinese character is encoded with 3 bytes in UTF-8, so two characters use 6 bytes total.