How do you solve the problem of variable length encoding storage and decoding?

[picturetxl]

After the implementation of character encoding, you need to encode each character and write it to a file. I saw your code. You write the code table to the file first and end with #, and then read each character in the test file. But I don't understand why you save the character encoding in a byte, It can also accurately extract the corresponding characters from the encoded binary file.
For example, a is encoded as 110, B is encoded as 01001, C is encoded as 1001010101, how do you do when ABC is stored in a file? At this time, the encoding of C has exceeded 8 bits. How do you restore these bits to the original ABC in the decoding process.