1) read about Middle-square method and implement it in C 
(https://en.wikipedia.org/wiki/Middle-square_method)
30 min

2) Main subject of the lesson: working with the files in C

a) Read about files I/O 
    e.g. https://www.programiz.com/c-programming/c-file-input-output
         https://www.programiz.com/c-programming/examples/frequency-character
         https://www.programiz.com/c-programming/c-file-examples
         https://www.tutorialspoint.com/cprogramming/c_file_io.htm

b) Write a program which will read the 'data.txt' file and process it in such a way that it will save only the words starting with 'a' letter (case-sensitive) omitting all other words. The order of lines should be preserved (the same as in the input file). The result should be stored in 'result.txt' file.

For instance for the file: 
"alexa ola as
ela cos
aleksander"

The result.txt should be:
"alexa as

aleksander"

c) Homework
Input: data.txt and k (integer)
Output: True/False 

Write the function which given the input text file and the number 'k' will return True if the number of words of length > 'k' is bigger than the number of words with length smaller or equal of 'k'. Otherwise the function shoult return False. The word ends with white space, EOF, EOL.*

Additional condition: 'k'>1

*Read about ('\r\n', '\n' vs. Windows, Mac, Linux)

Send NameSurnameLab52c.tar.gz with c code and pdf file containg the pseudocode of the program to lukaskoz@mimuw.edu.pl

Additionally, send Ex. 2b as NameSurnameLab52b.tar.gz containing 'pdf' file with pseudocode, c code, and two input and two output files (not more than 20 lines of max 200 chars per line in each file).

Deadline: 06.11.2018 11:00 (CET)

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Extra reading:
Get familiar with files such as:
*.csv (*.tsv), *.json, *.xml

Those are the most frequently used types of files for storing the data. All programming languages have libraries ready to read&write those formats and you will constantly use them in the future.