Working Out of the Kernel

X: Most intermediate/advanced programmers thinks it’s too difficult to work out of the kernel; it’s not impossible at all; for example.. to process a string and find a substring inside it, in node.js and c++, we will include a library, and use the substring() function.; For the fun of it, I decided not use that function, and manually iterate through characters in the string, and cut at desired position.; the performance difference for this action alone is about 2000%