1. Bitwise Operator #

Created Saturday 19 October 2019

• & - check even or odd → do k&1 → if answer is 1, then k is odd. Otherwise even.
• | checking for zero, do k | 0. If 0 comes, k is 0. else it is non-zero.
• ~ checking for 0, if the number after ~k == 0, then k is 0.
• ^ shortcut for checking equality, 0 if equal and 1 if unequal.

There are two bitwise shift operators:

• << operator. Shift to the left, pad with zeros.This does doubles the value for almost all numbers, except the ones with the second last MSB as 1 or 0, It flips the here.

• floored division with not truncation of decimal. Padding with 0 or 1 as per compiler, g++17 pads negatives with 1 and, positives with 0. e.g -23/2 = -12

• Using shift operators with negative integers is termed an undefined operator coz we cannot predict the output for all cases.

Resources

• https://codeforwin.org/2018/05/10-cool-bitwise-operator-hacks-and-tricks.html
• https://graphics.stanford.edu/~seander/bithacks.html