Thread: removing text from a file

  1. #1
    Registered User
    Join Date
    Nov 2005

    removing text from a file

    ok the answer to this is probably very simple, but i've never had to do it before and had no luck on google, so maybe someone here can help me. i have a .txt file that i'm writing to, using an ofstream, and i want to be able to delete a line from the file. how can i do this?

  2. #2
    Registered User
    Join Date
    Jan 2005
    Read each line into a linked list or even just an array (if you count the lines first). Then loop thru the linked list/array and output only the lines you want to a file.

  3. #3
    Super Moderator
    Join Date
    Sep 2001
    It's a common misconception that you can write, "part", of a file. What actually needs to be done, even if the concept in your mind is that of simpling adding or removing a line, is that every byte needs to be read into memory, edited by your program (often the new data is just read into a new array in memory), and then every byte is written back to the program.

  4. #4
    The Reel Thing
    Join Date
    Jun 2005
    Put every line into a vector, then find and remove the line you wish to delete, then iterate through the vector and place the lines back into the file.
    Bagpipes putting the fun back in funeral.

  5. #5
    Registered User
    Join Date
    Nov 2005


    thanks for the help guys. much appreciated.

  6. #6
    and the hat of int overfl Salem's Avatar
    Join Date
    Aug 2001
    The edge of the known universe
    Why would you want to read the whole file into memory?
    Surely just read each line, and write it out if you want to keep it, is much more efficient in memory terms.

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