Fastest way to find the number of lines in a text (C++)

Question

I need to read the number of lines in a file before doing some operations on that file. When I try to read the file and increment the line_count variable at each iteration u

Answer 1

It isn't slow because of your algorithm , It is slow because IO operations are slow. I suppose you are using a simple O(n) algorithm that is simply going over the file sequentially. In that case , there is no faster algorithm that can optimize your program.

However , I said there is no faster algorithm , but there is a faster mechanism which called "Memory Mapped file " , There are some drawback for mapped files and it might not be appropiate for you case , So you'll have to read about it and figure out by yourself.

Memory mapped files won't let you implement an algorithm better then O(n) but it may will reduce IO access time.