I have a somewhat odd and complicated question. Some background: I am trying to open up a file which contains formatted numerical data, find certain elements, and then overwrite these elements with corrected data.

So, my plan was to just iterate until I found the data, use .tellg() to get my the pointer, use .seekp() to find where I need to overwrite the existing data and then just simply .put() whatever I wanted. Simple enough right?

Then, I ran into some problems.

#1)Seekp() wasn't affecting where my .put() was going. Not at all. After a few hours, I fiddled around and found that seekg() was actually dictating where my .put() was going to be written. Here's where we descent into the twilight zone.

#2) Alright, I can deal with the strange reversal of seekg and seekp. Now, I find that wherever I .put() is something like 90 characters PREVIOUS to where my pointer should be. I tested this by setting my seekp and seekg to the same spot, reading whatever was there, setting the pointers back, then trying to put() a character. It invaribly showed up 98 characters before wherever I expected it to be.

#3) OK, I can deal with this too. I think. I'll just compensate for this weird offset right? Everything's going fine UNTIL.....

I realize that the space between where I want my pointer to be and where it actually is (The weird negative offset) changes. After five or six cycles of beautiful correct search+replacement, it fizzes out by one character and starts overwriting totally wrong stuff. This makes me sad.

One of my ideas of how to fix it requires the deletion of characters in a file. Actual, deletion... not overwriting with null or space. If I can actually delete a character, I think I can compensate for this weird offset.

So my questions are threefold:
1) Is there any way to actually DELETE a character in a file with C++?
2) What's with this weird offset and reversal of seekg/seekp?
3) Could all my problems arise from using fstreams as global variables?

Some of my mindless conjecture:
I declate my fstreams globally as such:

fstream statsFS;

and then open them in a function:

void reclassOne()
        int status;
        statsFS.open("3_statistics.dat", ios::out|ios::in);
        minmaxFS.open("3_minmax.dat", ios::out|ios::in);
11 Years
Discussion Span
Last Post by Dave Sinkula

I was hoping it wouldn't come to that... some of my files are 400+ MB...

What about other programming languages? Any of them offer simple file manipulation?

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