How to filter words from a file

I've been trying to make a swear filter for text documents where the program takes in strings at the command line and the text file but I am having problems figuring out how to do it.

Example application: (random words instead of swears)
filter.out i you me < filter.txt

filter.txt:
i love you, you hate me
from me

Output:
love hate
from

I understand how to print to files using fprintf and how to read and print out a file on its own. But how do I read it, remove the words I want and continue printing the file? I cant seem to figure it out. I'm using strncmp to try and compare, but once I compare them, I dont know how to replace it in the file.

You want to output all of the text to a new file (probably word by word in a loop), but skip the text that you don't want kept. Then delete the original file and rename your new one.