Inverse of left shift by 1

Question

I have the below equation.

A=B<<1. 

Could some one please tell me how I can get back B given A?

Answer 1

You can't. The highest bit of B is lost, and there is no way you can get it back.

Answer 2

You can simply use the right shift operator:

B = A >> 1

Details see

https://docs.oracle.com/javase/tutorial/java/nutsandbolts/op3.html

and this

Byte shift inverse operation