Create program in C programming language and include comments of explanation.

1. A user is prompted to type a free form sentence.

2. Create a link list dictionary of all the words in the sentence:

-For each word: Store the word length, store the first 4 letters of the word, and each entry points to the next as a linked list.

Do not use dynamic memory allocation routines like malloc/ free. Instead use global memory for your dictionary.

Do not use the strtok() function to parse words from your sentence.

3. Once the linked list is constructed, the program will sort the list alphabetically by reassigning point links.

4. Once the linked list is constructed, prompt the user to look up a word. The program will search and return the entry that matches (up to the first 4 letters)

5. Support adding entries to the current linked list. Ensure the new word gets added alphabetically to the list.

6. Support initializing (deleting) the current linked list and allow case sensitive and insensitive search modes.

Please assist with this programming code in C.

Provide lines of code and output of the code constructed please.