Your mission
Your first compiled C program. One job: output a specific line and exit cleanly.
See it in action
./helloHello World!
Your checklist
Constraints
- Expected file
hello.c- Allowed functions
write
“Wrong answer” teaches nothing.
Write C in the browser, graded byte for byte. Every failing test names the line, the column, the byte. The full verdict, Valgrind included, lands in milliseconds.
2 of 2 failing
Learning stays free.
Everything you can use today is free, and will stay free for students.
For now, we're self-funded. As more people join, server costs grow. We keep optimising how Grademe runs so we can welcome more learners without making it too expensive to sustain.
Our goal is for Grademe to cover its own costs. Our priority is paid partnerships with schools and training providers, so students can keep learning for free.
Future services may help fund the platform. The tools you use today will stay free, so everyone can keep learning and practising, whatever their budget.
Privacy, in plain words.
What we keep, why, and for how long.
Read our privacy policyYour account, saved code and progress are stored in Europe. Our privacy policy lists the providers we use, retention periods and how to request deletion.
No ads, and we never sell your data or pass it on. Only if you accept, we look at how you use Grademe, tied to your account, to find what to fix and improve. Only our team sees it, and the detailed record of each visit is deleted after 90 days. Otherwise, visits are only counted anonymously.
Sign in with GitHub, Google or an email code. There's no Grademe password to create or store. Technical logs help us fix bugs and protect the service.
Explore Grademe.
A full C learning path is available today, from your first program to memory management. Python, JavaScript and more languages are coming soon.
Learn C
A guided path, with a checkpoint after each chapter.
Exercises
One problem at a time. Feedback from real tests.
Challenges
A series of exercises. One clock.
Studio
Write your own exercises and challenges. Share them with everyone.
Daily Challenge
A daily puzzle. Other learners' approaches to explore.
C Visualizer
Step through variables, pointers and memory. On desktop.
CLI
Take challenges in your terminal, with your own editor.
GitHub sync
Publish your passing solutions to a repository you own.
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