Pseudocode is an informal notation for describing an algorithm as a sequence of structured, human-readable steps. It borrows the control structures of real programming languages, such as loops, conditionals, and assignments, but deliberately leaves out the exact syntax, declarations, and boilerplate that a particular language would require. The goal is to communicate what an algorithm does to a person, not to be compiled and run.
Because it is not tied to any one language, pseudocode lets an author focus on the essential logic of a method and lets readers translate it into whatever language they use. It is the standard medium for presenting algorithms in textbooks and in algorithm design, where committing to C, Java, or Python would distract from the idea and tie it to one ecosystem.
The most influential example is “Introduction to Algorithms” by Cormen, Leiserson, Rivest, and Stein, known as CLRS, which presents nearly all of its algorithms in a consistent pseudocode style using indentation to show block structure. The authors maintain a freely available MIT Press document, “Using the clrscode4e Package,” written by Thomas Cormen, that defines exactly how this pseudocode is typeset, underscoring how deliberately the conventions were designed for clarity.
Pseudocode trades precision for readability: it can quietly leave details ambiguous that a compiler would reject, and different books adopt slightly different conventions. That informality is the point. It lets the reader see the shape of an algorithm before worrying about the mechanics of a specific language.