C# undo file.ReadLine()

Question

I am reading huge textfile (1.8 GB) with

     while ((j = file.ReadLine()) != null) {...}

However, after some operations i got myself into situation, when I would like to 'undo' last ReadLine, so the next ReadLine would actually read exactly the same line.

Is there any way to do it? :)

The same job would do 'looking at next character' without any reading, so that I could, based on this character, decide if I want to read next line or not.

example:

    >1
    abc
    def
    >2
    ghi

After I read 'def' with ReadLine() I want to know if the next line contains '>' character or if there are just letters of alphabet.

Thanks a lot.

Answer 1

For just 'looking at next character', use the Peek() method:

http://msdn.microsoft.com/en-us/library/system.io.streamreader.peek(v=VS.100).aspx

Answer 2

For looking at the next character you can use the method Peek.

This will return the next character without changing your location in the file.