Online C++ playground
Write and run C++ right here — it executes in your browser, so there's nothing to install and nothing to sign up for.
65 practice problems, auto-judged 16 plain-English guides zero setup — runs in your browser
Program input (stdin) — click to add input for cin
Runs locally in your browser — avoid infinite loops (while (true) without a break), since the page will wait for them. Compiles your first steps toward C++20? The engine currently covers the beginner core (iostream, cstdio, cmath and friends).
Auto-judged practice
65 problems from first input to knapsack, backtracking and grid spirals — write your solution and the browser grades it test by test.
Plain-English guides
16 guides that explain the why, not just the what — every snippet runnable right on the page, phone included.
Beginner course
Seven lessons from first output to pointers — runnable, in order, with matching practice.
Interview ready
Beginner screening questions with short, say-it-out-loud answers — pointers, memory, types and traps.
Where to go next: pick an example above and press Run, or start at the Hello World lesson. The editor below remembers your draft, and stdin is one click away for programs that read input.