# c-sum — cross-platform C example

Minimal example: a C program that reads `N` then `N` integers and prints their
sum. Tested with `judge` across **gcc / clang / MSVC** on **Linux / Windows**,
with optional **valgrind** and **sanitizer** runs.

## Files

- `solution.c` — student-facing solution (could be what the student submits)
- `sum.jdg` — judge test suite
- `.gitea/workflows/judge.yml` — Gitea CI matrix

## Run locally

```sh
# Linux / macOS
CC=gcc   judge sum.jdg .
CC=clang judge sum.jdg .

# With valgrind
judge sum.jdg . --wrapper="valgrind --error-exitcode=99 --leak-check=full -q"

# With ASan+UBSan build
CC=clang CFLAGS="-O1 -g -fsanitize=address,undefined" judge sum.jdg .
```

On Windows (inside an MSVC dev cmd shell), `build_windows` kicks in and
produces `solution.exe`, which the runner auto-detects.

## Notes about the `.jdg`

- `normalize_crlf = true` — Windows `printf` emits `\r\n`; we strip `\r` before
  matching so the same expected outputs work on both platforms.
- `trim_trailing_ws = true` — forgives trailing spaces a student's output might
  pick up (rare but annoying to debug).
- `binary = "solution"` — the runner tries `solution` first, then
  `solution.exe` on Windows automatically.
- Per-group `scoring = all_or_none` on `stress` gives weight only if every
  stress test passes.

## Adapting the Gitea workflow

- `runs-on: ${{ matrix.toolchain.system }}-Runner` assumes you have
  self-hosted Gitea runners labelled `Linux-Runner` / `Windows-Runner` (same
  naming as your existing `fixed_floating` pipeline).
- `secrets.VAR_TOKEN` is only needed when pulling a student repo from a
  private org.
- The summary job shells `grep` over the JSON; swap to `jq` if available on
  your runners.