Purdue CS 18200: Foundations of Computer Science
CS 18200 is Purdue's discrete math course for CS majors (logic, proofs, sets, functions, induction, counting, graphs, and basic complexity), usually taken alongside or right after CS 18000. It's the course where CS stops being programming and starts being mathematics.
Fennie is independent and not affiliated with Purdue University. This is an unofficial study guide.
What makes it hard
Proofs are the wall: most freshmen have never had to construct a mathematical argument, and induction in particular feels circular until it suddenly doesn't. Exam questions present unfamiliar claims to prove or disprove, so memorizing homework solutions fails completely; the course tests whether you can produce reasoning, not recall it.
What you'll cover
- • Propositional and predicate logic
- • Proof techniques and induction
- • Sets, functions, and relations
- • Counting and combinatorics
- • Graphs and trees
- • Big-O and growth of functions
The CS 18200 study guide
How to study for Purdue CS 18200, step by step.
- 1
Rebuild every proof from a blank page
Reading a proof and nodding is not the skill CS 18200 grades. After studying any example, close the notes and reproduce the full argument yourself. The gap between recognizing and producing proofs is where exam grades are decided.
- 2
Master logic notation until it's a language
Quantifiers, implications, and negations are the alphabet for everything after. Practice translating English claims into formal statements and back until negating a nested quantifier costs you no thought.
- 3
Give induction triple the practice you think it needs
Induction is the course's famous wall and the technique later CS courses lean on hardest. Work many inductive proofs across different structures (integers, sums, recursive definitions) until the template stops feeling circular.
- 4
Do unfamiliar problems on purpose
Exams present claims you haven't seen and ask you to prove or disprove them. Pull extra problems from the textbook's unassigned sections so you're practicing production, not pattern-matching homework.
- 5
Connect each topic to the CS it powers
Induction underlies recursion correctness, counting underlies probability and algorithm analysis, graphs underlie half of CS 25100. Knowing why each topic matters keeps the abstraction motivated and memorable.
Today's CS 18200 plan
What a Fennie Daily Plan looks like for CS 18200. Yours is built from your syllabus and adapts every day to your deadlines and progress.
- Review: Sets, functions, and relationsReview · 25 min
Work back through the CS 18200 material on sets, functions, and relations. In the app, Fennie builds this from your own notes and syllabus.
- Practice: Counting and combinatoricsPractice · 20 min
Targeted problems on counting and combinatorics, the kind CS 18200 actually tests.
- Quick quiz: Graphs and treesQuiz · 10 min
Five generated questions to expose weak spots on graphs and trees before the exam does.
- Preview: Big-O and growth of functionsPreview · 10 min
A first pass over big-o and growth of functions so the next session starts from familiar ground.
First plan free, no card required. Fennie is independent and unaffiliated with your school.
FAQ
Is CS 18200 at Purdue hard?
It's a different kind of hard than CS 18000: no coding, all mathematical reasoning. Students comfortable with proofs find it manageable; students meeting proofs for the first time (most of the room) need consistent weekly practice to get over the induction wall.
How do I study for CS 18200 exams?
Produce proofs from a blank page rather than rereading solutions, and practice on claims you haven't seen; that's the exam format. Drill logic notation and induction hardest. They're the foundation for everything else in the course and most of what exams weight.
Why does CS 18200 matter for later courses?
CS 25100 assumes its induction, counting, and graph material fluently for algorithm analysis and correctness arguments. Students who scrape through 18200 on partial understanding consistently report paying for it in the sophomore core.
More Purdue courses
CS 18000: Problem Solving and Object-Oriented Programming
CS 18000, universally called CS 180, is Purdue's first course for CS majors: object-oriented programming in Java, from control flow and methods through classes, inheritance, interfaces, exceptions, file I/O, and concurrency basics. It's the famous freshman gauntlet that sets the tone for the entire Purdue CS core, with labs, projects, and exams that include writing real code.
CS 24000: Programming in C
CS 24000 teaches C to students who already know Java from CS 18000 (pointers, memory management, structs, dynamic allocation, and the machine-level view of data) as preparation for the systems half of the Purdue CS core. Homework is programming-heavy and exams test C semantics in detail.
CS 25000: Computer Architecture
CS 25000 covers how computers actually work, from transistors and logic gates up through combinational and sequential circuits, datapaths, assembly language, and memory hierarchy. It's one of the two sophomore-core courses (with CS 25100) that Purdue CS students take after the freshman sequence.
CS 25100: Data Structures and Algorithms
CS 25100 is Purdue's data structures and algorithms course (lists, trees, heaps, hash tables, graphs, sorting, and algorithm analysis) and the most notorious course in the CS core. It gates the upper-division CS curriculum and its exams have a campus-wide reputation for difficulty.