rading a file

fanatic_ravi · 02-03-2005, 08:29 AM

How should i replace a line in a file thru a C program

itsme86 · 02-03-2005, 09:28 AM

You can't, unless the new line is the exact same length as the old line. You'll have to read in the old file and write it back out to a new file with the line modified.

fanatic_ravi · 02-03-2005, 09:53 AM

how do i search on a particular line ...shall i have to strtok on the lines or what ??

itsme86 · 02-03-2005, 10:16 AM

You can use strchr() to look for a specific character in a string, or you can use strstr() to look for a substring in a string. It depends on what you want to search for.

harken · 02-04-2005, 01:53 AM

My 20c in here:
If the file is structured in lines maybe you could do this

pen the file r/w, read it line by line, compare the line with whatever string you want; when found, fseek to the line's position-1, write the desired line, fseek to the new location then write the rest of the lines skipping the one found.

edit: maybe it's not clear what I said above but of course you'll have to use a temporary file which then can be renamed to the original file, previously deleted.

JrLz · 02-04-2005, 09:35 PM

Agree with harken....
You can do anything with that.......
wueheheh