When using the >> operator, what happens to the sign bit in a right shift operation?

• A. It is always replaced by zero
• B. It is preserved
• C. It is ignored
• D. It is shifted out

Answer: (B)

In a right shift operation when using the >> operator, the sign bit is preserved. This operator performs what is known as an arithmetic right shift, which maintains the sign of the original number.

For positive numbers, the sign bit is 0, and performing the right shift will right-align the bits, effectively dividing the number by two for each shift and filling the leftmost bits with zeros. However, for negative numbers, where the sign bit is 1, the right shift operation will keep filling the leftmost bits with 1s. This maintenance of the sign bit ensures that the value of the number retains its correct sign after the operation.

Thus, when using the >> operator, the operation not only shifts bits to the right but also ensures the correct representation of negative values is preserved, which is why the sign bit is maintained.