Efficiently reading a very large text file in C++

Question

I have a very large text file(45GB). Each line of the text file contains two space separated 64bit unsigned integers as shown below.

4624996948753406865 10214715013

Answer 1

I can only guess that the bottleneck is in:

string str(memblock);

-Because you allocate a 45MB long segment in memory.

You should read the file line by line, as described in here:

• Read file line by line

In order to profile your program, you can print clock() between each line, as described in:

• Easily measure elapsed time