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I think for long time, new C language programmer is getting rare. As I'm solving the Eudyptula Challenge, an idea came to me that similar challenge is necessary for C language.

I'm not sure what tasks are suitable and how mant tasks are necessary..actually I have no plan yet. But I'll write some tasks from printing "hello-world" to making a class with a function pointer. If you have an idea, please send me pull-request.

discussion on reddit

  • pnpbios
    • Writing your own daemon, your own PAM module, writing a custom network interface, writing your own shell

topics:

  • file IO
    • creating ls
  • concurrent
  • network
    • making chatting program
  • memory
    • make pool-based memory allocator
  • error handling
  • toolchain: preprocessor, compiler, linker
  • cache
  • assembly
  • performance
  • syncronization

print "Hello world!"

Use argc and argv to print "Hello world!".

$ print 3 "Hello world!"
1 Hello world!
2 Hello world!
3 Hello world!

read directory and file

make ls tools that just print names of specified directory.

  • do not need to get no options

command argument

make ls tools with options and do command argument parsing with getopt, getopt_long

  • short options: -l, -a, -d
  • long options: --long, --all, --directory
  • -l(--long) option prints size, permission, user id, last modified time.
  • use getopt, getopt_long to process options

multi-thread find

make find program that has multi-threads

  • get file-name and directory-name
  • check how many directory exists in target directory
  • creates threads as many as directories
  • one thread finds a specified file in one directory
  • compare performance of one-thread find

make chat

make a 1:1 chatting program for terminal

  • make server & client
  • support IPv4 and IPv6

make ftp

make ftp server & client

  • server-side usage: ftp-server
  • client-side usage: ftp-client <IPADDR> <FILE-NAME>
  • print '#' characters to show file-transfer is working
  • make server as daemon
  • server should support multi-connection

make streaming player

clients send sequential images and server shows images

  • convert a gif image into many jpeg images
  • client sends the jpeg images
  • server receives the jpeg images and shows
  • server supports many windows, each windows shows images from a client
  • use gtk or win32 APIs

data-driven code

Make serial number certification program

  • certificate a serial number file
  • read spec.rc file to specify serial number format
  • encode user information, user-account number, name, product id, in serial number
  • decode the information from the serial number
  • serial code is printed in BASE64 code.
  • use any encryption algorithm
$ cat spec.rc
# field length
user-account 4
user-name 16
product-id 4

$ encode-serial spec.rc
user-account: 1234 <user-input>
user-name: gogostar <user-input>
product-id: 5678 <user-input>
abcd-defg- <output>

$ decode-serial
serial: abcd-defg-xxxx-xxxx <input>
account: 1234
name: gogostar
product: 5678

pool-based memory allocator

make a pool-based memory allocator

  • create pool as many as number of CPUs in your system
  • each thread allocates memory from a pool of its own CPU
  • apply your allocator to any multi-thread program and compare performance
    • LD_PRELOAD=${PATH}/lib/libyourallocator.so.1 app

make a shell

make your own shell

  • features
    • pipe
    • redirection
    • background running
    • stdin, stdout, stderr
$ myshell
THIS-IS-MYSHELL> ls
a b c
THIS-IS-MYSHELL> ls > files.txt
THIS-IS-MYSHELL> cat ls
a b c
THIS-IS-MYSHELL> ls | cat > files.txt
THIS-IS-MYSHELL> asdf 2> error.txt
THIS-IS-MYSHELL> cat error.txt
command is not found

More challenges

Remember! Design is more than the implementation. Think scalability!