Arithmetic bit-shift on a signed integer

Question

I am trying to figure out how exactly arithmetic bit-shift operators work in C, and how it will affect signed 32-bit integers.

To make things simple, let\'s say we w

Answer 1

As of c++20 the bitwise shift operators for signed integers are well defined.

The left shift a< is equivalent to a*2^b modulus 2^N where N is the number of bits in the resulting type. In particular 1<<31 is in fact the smallest int value.

The right shift a>>b is equivalent to a/2^b, rounded down (ie. towards negative infinity). So e.g. -1>>10 == -1.

For some more details see https://en.cppreference.com/w/cpp/language/operator_arithmetic .

(for the older standards see the answer by Matthew Slattery)