Goal for this part
Edit the selected byte value.
Treat 07-Edit-Byte as the source of truth for this checkpoint. If your local tree drifted, re-clone that folder rather than mixing files from neighbors.
What you should already know
You do not need prior egui experience for part 1. Later parts assume you finished the earlier snapshots on the same machine.
- A Rust toolchain (
cargo) is installed - You have a desktop session for the egui/gtk window
Why egui fits Bytequarry
egui is an immediate-mode GUI in pure Rust. A hex editor is a focused way to teach binary buffers and selection without a webview.
Draw offset, hex, and ASCII columns in a scrollable grid. Keep the byte buffer behind a small document struct.
After you run the snapshot, you should recognize the behavior described in the goal—before you move on. If the window (or server) never appears, stop and fix the run steps.
Code shape
Snapshots stay small on purpose. Look for this kind of core call as you read the folder:
buffer[offset] = value;How to run it
Clone the teaching repo, open 07-Edit-Byte, install what the README asks for, then run cargo run.
git clone https://github.com/michaeldunga1/fcc-egui-hex.git
cd fcc-egui-hex/07-Edit-Byte
cargo build
cargo runCommon mistakes
- Ignoring platform-specific install notes in the snapshot README
- Hard-coding paths that only work on your machine
- Skipping confirmation on destructive actions
- Mixing secondary-model IDs with primary ones