Deleting rows in a file

[QueryWriter]

Hi guys, I'm a SQL programmer, not very good in C.
From a C program, I want to open a file (done), remove the 3rd and 5th rows and then close it.
I go on reading the file char by char, usign \n delimiters to count rows, then when I'm in the row I want to cancel, how can I obtain my goal?
MTIA
Ronald

 

[QueryWriter]

I know it's in fact not so much stimulating!