A Level Computer Science OCR Practice Exam

What is the first step in converting a number to Two's Complement?

1. Add 1 to the number

2. Flip all the binary digits

3. Represent the number in decimal

4. Output the number as a string

The correct answer is: Flip all the binary digits

To convert a number to Two's Complement, the first step involves flipping all the binary digits of the number. This process is known as finding the one's complement. When you have a binary representation of a number, flipping the digits means changing all 0s to 1s and all 1s to 0s. This inversion is essential in forming the base for the next step in the Two's Complement process, which is adding 1 to the flipped result to arrive at the final Two's Complement value. Understanding this step is crucial as it forms the backbone of how negative numbers are represented in binary systems. It allows for the seamless inclusion of negative integers within the same binary framework used for positive integers. Therefore, flipping the binary digits is indeed the correct first action in the Two's Complement conversion process.