Deleting the last set of data written in text file

This is a discussion on Deleting the last set of data written in text file within the C Programming forums, part of the General Programming Boards category; Hi everyone, I have a problem here, I had tired to log a few set of data inside a text ...

  1. #1
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    Deleting the last set of data written in text file

    Hi everyone,

    I have a problem here, I had tired to log a few set of data inside a text file before running a couple of function. Is there anyway to delete the data entered at the end of the program if there was no error in my function?

    thanks alot!!

  2. #2
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    One way:
    Store all the information you want to write to the log in memory - a string array will work.
    When the program comes to an end, then decide what pieces of the information you want to write to the log.

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    I think he wants to delete the file he reads from after the program terminates. Is that right ?

    If it's the case, look at the remove function.
    Teacher: "You connect with Internet Explorer, but what is your browser? You know, Yahoo, Webcrawler...?" It's great to see the educational system moving in the right direction

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    I understand that I could have write it in the memory, but what if the program crushes before it can log all the information? Is there any other way to remove the data instead of read and rewrite all the data? All I need is to remove the last data that was log.

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    You could read your data from one file, then write to another file (say log2). If your program crashes, log2 will contain up to where your program got before crashing.
    Teacher: "You connect with Internet Explorer, but what is your browser? You know, Yahoo, Webcrawler...?" It's great to see the educational system moving in the right direction

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    You could record the tell position within the file before you start writing your information to it. If your program completes successfully, you seek to that position and erase the remainder of the file. This of course assumes that you have other information in the file before your program writes to it and you wish to preserve it and also that you don't want to work with a copy of the original file.

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    Thanks Happy reaper

    Let say if I want to keep it in one file? Is there a way to do it? Is there a way to go back to the last entry and overwrite the last entry if there is no error occur?

  8. #8
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    ftell() and fseek() or lseek() and ltell() depending on how you open the file in the first place.

  9. #9
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    Well, if you really wanted to keep the name "log" for your file, just before your program concludes, you delete "log", and after that you could rename "log2" to "log", but if to keep that name during runtime, well, I don't know of a way to do that.
    Teacher: "You connect with Internet Explorer, but what is your browser? You know, Yahoo, Webcrawler...?" It's great to see the educational system moving in the right direction

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    Hei,

    Thanks I guess I get it.

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