I'm trying to find something of a backspace action to be done on files.
Something like:
- I for(i=0;i<n;i++) fprintf(file,"some text,\n");
- and I want to erase the last 2 characters \n and , and replace them with . (like two backspaces and a . )
I tried smthing like:
from what I guess \b deletes the next two char (i want something to delete the previous)Code:#include<stdio.h> int main() { printf("test.\n"); printf("\b\b,\n"); return 0; }
Last edited by spank; 08-27-2007 at 03:06 AM.
Use fseek() to adjust the point you write to in a file.
Though you need to be pretty careful when dealing with text files.
If you dance barefoot on the broken glass of undefined behaviour, you've got to expect the occasional cut.
If at first you don't succeed, try writing your phone number on the exam paper.
I thought about that... but I hopped that there was something like a \b approach to it.
\b is a character just like any other, except the terminal interprets it differently.
You can only alter the values of bytes in-place. If you want to remove or insert bytes from a file, you have to either buffer a bunch of data in memory, or use a temporary file. Basic idea:
Code:while not end of file: read bytes from input alter the bytes and write them to the output (a NEW file) end while copy temporary file back over the original file
