Need a little help with file handeling

Hi

I have partly made a program that is supposed to be able to execute a search and replace action from lets say a batch file or a shortcut.
I have managed to make the program accept the inputs, so basicly all i need now is the search and replace function :)

I have never done anything with files before (ok, i have used a_file<<" "; to write to a file, but thats not exactly what im after) so i basicly dont know where to look.

Does someone know a good tutorials for file handeling ( preferably something that includes something relevant to what im after ) or just file handeling in general.

My compiler is Dev-C++ and this program only needs to work on windows (xp) which is the OS im using.

Im sorry if this has been answered before, i used the search function, but couldent find anything relevant :(

Thanks in advance.

~DumAzz~

P.S (Yes, im new to c++)

There are tutorials on the homepage of this site.

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Mats

You can check here to get a feel for how to use ofstream. I believe you should be able to use seekp to set the position of the file pointer then write to write there.

There are examples there to help you out as well.

I hope I was of help,

cs_student.

Quote:

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Originally Posted by matsp

There are tutorials on the homepage of this site.

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Mats

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I have gone through that tutorial, but thanks anyway :)

Quote:

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Originally Posted by cs_student

You can check here to get a feel for how to use ofstream. I believe you should be able to use seekp to set the position of the file pointer then write to write there.

There are examples there to help you out as well.

I hope I was of help,

cs_student.

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Thanks cs_student, that page contained A LOT of good material i can use :) however, i didnt find a function that allows me to search for a string.:(




How do you search for a string and where is in the word are you after you have searched (infront of it or behind it?)? I need a search function sinced i dont know where in the file the word is.

Thanks
~DumAzz~

You don't search for a string in a file, you read the file contents in and search while reading or search the contents after you have saved them somewhere.

Code:

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open input file for reading
open temporary output file for writing

while you can read input file line into variable:
    check variable for position of search string
      (how you do this depends on whether you're using C-style character arrays or C++ std::string objects)
    if search string is not found:
      write contents of variable to file
    else:
      write contents of variable, up to, but not including the found location, to file
      write replacement string to file
      move search string pointer to location immediately following search string
      write contents of remainder of variable to file
    end if
end while loop

close both files
copy temporary file over original file

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Quote:

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Originally Posted by rags_to_riches

Code:

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open input file for reading
open temporary output file for writing

while you can read input file line into variable:
    check variable for position of search string
      (how you do this depends on whether you're using C-style character arrays or C++ std::string objects)
    if search string is not found:
      write contents of variable to file
    else:
      write contents of variable, up to, but not including the found location, to file
      write replacement string to file
      move search string pointer to location immediately following search string
      write contents of remainder of variable to file
    end if
end while loop

close both files
copy temporary file over original file

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Hmm, i understand how that would be a good way to make it, but i still need to find out how to do the different tasks. well, i guess ill go one step at the time :)

Quote:

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Originally Posted by rags_to_riches

Code:

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while you can read input file line into variable:

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First i input whole file into a string? (or can you put anything else then numbers in variables?) And the file might be multiple lines, but i guess that dosent matter?

Quote:

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Originally Posted by rags_to_riches

Code:

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check variable for position of search string
(how you do this depends on whether you're using C-style character arrays or C++ std::string objects)

---

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i think im using c++ std::string objects, so how do i search in a string (where can i find it out)

Quote:

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Originally Posted by rags_to_riches

Code:

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move search string pointer to location immediately following search string
      write contents of remainder of variable to file

---

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I guess i just loop the search for string untill eof (end of file (or string in this case))? since the document might contain more occurences of the word to search for.

Im sorry if i seem slow, or annoying, but like i said, im kinda new to c++ and its late here , AND my head is spinning from all the reading ive done today. Bare with me :)

~Dumazz~

Edit: im going to bed, i REALLY REALLY NEED IT... ;)

That solution, by the way, assumes there would only be one match per line of input.

Here's a good place to get started: C++ Reference

Quote:

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Originally Posted by rags_to_riches

That solution, by the way, assumes there would only be one match per line of input.

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i see, but i guess looping the search function would solve that problem.
or if that dosent help, ill figure something else out....tomorrow :)
Thanks for all the help so far

~Dumazz~

Hey.

Ok i have managed to put the first line of the file into a string / character array.

how do i search through a/the string/ character array?

~DumAzz~

Everything you need is on the C++ Reference site to which I linked.

i found it now..
Thanks for all your help, ill finnish up the project and post the content here when im done.
Special thanks to cs_student for good link and VERY special ;) to rags_to_riches for helping a lot.

~DumAzz~

so..i finished the first version of the code (i know it took long, but i had some stuff to do...like my birthday :) :) ) anyway...i know it will error if you try to replace "test" with "test test" since it will find that 2nd one too, but i will fix that later (by searching for found+(argv[3]'s length).

if there was anything else, i'dd be happy to get feedback ;)