how to modify a txt file

[Jerry]

Hi, everybody:

I want to modify a portion of a txt file. The way I do it is to
open the file in read mode, and create a new file, and delete the old
file, and rename the new file.
I am wondering if this is a common practice of modifying a file in
C, is there any other way to do it?
Thank you all for your attention.


--Jerry

 

[Jacob Oost]

Hi, everybody:

I want to modify a portion of a txt file. The way I do it is to
open the file in read mode, and create a new file, and delete the old
file, and rename the new file.
I am wondering if this is a common practice of modifying a file in
C, is there any other way to do it?
Thank you all for your attention.


--Jerry

Couldn't you just open a new file for reading or writing?

fptr = fopen("filename", "r+");

Of course you'd do the standard error-checking. I'm new to this but
isn't that what you want? According to my book, "r+" opens an existing
file for reading or writing.

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...... END GEEK CODE BLOCK ----

 

[Jerry]

Thanks, if it is just adding stuff at the end of an existing file, I'd
use your approach. But modifying the txt involves deleting things in a
file, and "inserting" things in the middle of a file. I am wondering if
there is a way to delete things in a file. Meanwhile, I dont think
"write" is as same as "insert", cause the file pointer does not care
what's already in there, and it will just erease things in the existing
file. therefore, if we want to use r+ mode, we need to take care of a
lot of things.

 

[CBFalconer]

I want to modify a portion of a txt file. The way I do it is to
open the file in read mode, and create a new file, and delete the
old file, and rename the new file.
I am wondering if this is a common practice of modifying a file in
C, is there any other way to do it?

Yes, in any language. However you might think about how to recover
if any of those steps fail, and how to detect those failures.

 

[Jerry]

Thank you very much.

Yes, in any language. However you might think about how to recover
if any of those steps fail, and how to detect those failures.

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