21.6. Encoding Messages

Try these first

1. 1.

   What is the main purpose of encoding messages?

   Hint

   Think about how computers understand data.

2. 2.

   Define a prefix code in your own words.

   Hint

   Consider how decoding would work with such a code.

3. 3.

   What does variable length encoding do?

   • Uses the same number of bits for all characters
   • Uses different lengths based on frequency
   • Only applies to certain languages

   Hint

   Think about how frequent letters would be represented.

4. 4.

   True or False: Prefix codes can lead to ambiguous decoding.

   • True
   • False

   Hint

   Consider how decoding works with non-prefix codes.

5. 5.

   You have the frequencies: X=0.5, Y=0.25, Z=0.15, W=0.1. Create a Huffman tree and assign codes based on your construction.

   Hint

   Pair the least frequent nodes first to build the tree iteratively.

6. 6.

   If the average length of encoded bits per letter for a given alphabet is calculated as 3.5, and you redesign the encoding to reduce it to 2.8, explain the impact on data transfer.

   Hint

   Think about how much space bytes take up and how averages affect large data sets.