Computer Science Tools

Convert between binary, decimal, hexadecimal, and octal. Bit-level visualization, ASCII lookup, and step-by-step conversion methods.

Enter Boolean expressions with AND, OR, NOT, XOR, and IMPLIES to generate complete truth tables. Detects tautologies and contradictions.

Watch bubble, selection, insertion, merge, and quick sort in action with color-coded bars for comparisons, swaps, and sorted elements.

Compare O(1), O(log n), O(n), O(n log n), O(n^2), O(n^3), and O(2^n) on an interactive graph. See operation counts at any input size.

Select predefined circuits with AND, OR, NOT, XOR, NAND, NOR gates. Toggle inputs and see outputs update in real time with auto-generated truth tables.

Enter a regex pattern and test string to see highlighted matches, capture groups, match count, and a plain-English pattern explanation in real time.

Visualize BFS, DFS, Dijkstra, and A* on an interactive grid. Draw walls, set weighted cells, generate mazes, and watch each algorithm explore step by step.

Visualize stacks, queues, linked lists, binary search trees, and min heaps with animated operations. Push, pop, insert, delete, and traverse step by step.

Build and test finite state machines (DFA/NFA). Create states, define transitions, and test input strings with step-by-step animation showing the machine processing each symbol.

Build a binary search tree and watch inorder, preorder, postorder, and level-order traversals step by step with animated SVG node highlighting and numbered visit badges.

Visualize packet routing through network topologies. Animate Dijkstra's shortest path, explore TCP/IP layers, simulate traceroute, test fault tolerance by disabling nodes, and fragment packets.

Explore Run-Length Encoding and Huffman coding for text, and pixel-level image compression. Build Huffman trees, paint pixel grids, compare lossless vs lossy compression ratios.

Visualize Java arrays, ArrayLists, and 2D arrays step by step. Selection sort, insertion sort, binary search, and all ArrayList methods with animated operations and Java code.

Encrypt and decrypt messages with Caesar, substitution, Vigenère, XOR, and simplified RSA ciphers. Visualize step-by-step encryption, frequency analysis, brute force attacks, and hash avalanche effects.

Step through recursive function execution with animated call stack frames and recursion trees. Visualize factorial, fibonacci, merge sort, binary search, and tower of hanoi with memoization toggle.

Visualize Java OOP concepts with heap/stack memory diagrams. Create objects, make aliases, call methods, and explore reference semantics, scope, and inheritance with step-through execution.

Practice debugging Java code and writing unit tests. Find the bug in 20+ code snippets, write test cases that catch hidden bugs, and browse a reference guide of 16 common Java errors.

Visualize Java String methods interactively. See charAt, substring, indexOf, equals, replace, and more with character-by-character SVG diagrams, == vs .equals() comparison, method chaining, and code tracing.

Guide a robot through a grid by building step-by-step sequences of commands. Learn how computers follow precise instructions - the foundation of all programming.

Build repeat loops to create color tile patterns. Discover how loops let computers do the same action many times without writing the same step over and over.

Build IF/THEN/ELSE rules and watch animated characters respond to changing conditions. Learn how programs make decisions - the heart of all computer logic.

Find and fix bugs in short robot programs. Learn how programmers debug code by reading it step-by-step and testing to see where things go wrong.

Draw pixel art on an 8x8 grid and see how images are stored as numbers. Encode and decode secret messages using the Caesar cipher - A=1, B=2 and a shift.

Make a cat sprite react to clicks, timer ticks, and key presses. Build event rules by picking a trigger and an action, then create a 3-scene animated story.

Sort information cards into safety bins and practice making smart decisions in internet safety scenarios. Learn what is OK to share online.

Watch a message split into numbered packets, travel through routers, and reassemble at the destination. Break a router and see packets reroute.

Classify computer components as input, output, processing, or storage. Explore what breaks when parts are removed and trace paths for common tasks.

Design a survey, tally responses, and explore the results with a live bar graph. Answer interpretation questions about the data. Grades 2–5.

Create named score jars, build a step-by-step program with Add, Subtract, Set, and Reset blocks, then run it and watch the values change. Grades 3–5.

Run the k-means algorithm step-by-step on 2D data. Six preset datasets including blobs, two moons, concentric rings, and anisotropic clusters illustrate where k-means succeeds and fails. Adjust k from 1 to 8, choose random or k-means++ initialization, and watch centroids move as you click step-iterate or run-to-convergence. Live readouts of WCSS inertia and silhouette score. Click to add custom points or load presets.

Three pre-canned scenarios (loan approval, college admissions, resume screening) show how a naive classifier produces unequal outcomes across demographic groups even when overall accuracy is high. Compare naive vs debiased predictions side-by-side with per-group accuracy, true positive rate, false positive rate, and demographic parity gap. Includes four real-world cautionary tales (COMPAS, Apple Card, Amazon hiring, Optum healthcare).

Type any text and watch how a language model breaks it into subword tokens, turns each token into a vector, and links them with self-attention. See token counts, the context window, and causal masking. Tokenization is approximate and the vectors are illustrative.

Write SELECT, JOIN, WHERE, and GROUP BY queries against small sample tables and see the result set plus the logical query plan. A teaching subset of SQL that runs entirely in your browser, no setup required.

Write a tiny assembly program and step through the fetch, decode, and execute cycle. Watch the program counter, registers, memory, zero flag, and output change one micro-step at a time, with labels and conditional jumps.

Run commit, branch, checkout, merge, and rebase on an in-memory repository and watch the commit graph, branches, and HEAD update live. See fast-forward versus three-way merges, merge conflicts, and how rebase rewrites history.