What is an algorithm in computer science?

An algorithm in computer science is fundamentally defined as a step-by-step procedure or formula for solving a problem. This definition captures the essence of what an algorithm is: a well-defined set of rules or instructions that can be followed to achieve a certain outcome or solve a specific task, often involving computations or data processing.

Algorithms are critical to computer science because they provide the methodologies needed for executing tasks reliably and efficiently. They can range from simple processes, such as adding two numbers together, to complex operations like sorting large datasets or searching through databases. The clarity and deterministic nature of algorithms, where given a particular input they produce a consistent output, make them a foundational building block in computer science.

In contrast, the other options provide descriptions that do not capture the essence of what an algorithm is. Data structures concern how data is organized and stored within a computer, programming language syntax deals with the rules for writing code in specific languages, and performance optimization involves techniques to make software run faster or use fewer resources. While these concepts are important in computing, they do not define an algorithm itself.