C Language Assistant · Technical Support

This app provides complete lessons, classroom labs, project editing, and bounded local code execution. This page summarizes quick start, execution boundaries, purchase restoration, and frequently asked questions.

Last updated: 2026-8-12

Quick Start

Open a built-in sample in the workspace, or tap “New Project.”
Edit the main.c in the editor; when input is required, use the console toolbar to set the virtual standard input.
Tap “Run.” Program output appears in the console, and syntax and runtime hints appear in diagnostics.
Read chapters in lessons, or choose a lab from exercises that creates an editable project.

Frequently Asked Questions

Why does the code report “Unsupported”?

This app provides a bounded interpreter designed for learning scenarios, not Clang, GCC, or a full ISO C toolchain. Syntax, headers, or functions outside the current educational subset show clear diagnostics.

Why does the program stop automatically?

The app limits instruction count, call depth, input volume, and output volume. Infinite loops, excessively deep recursion, or sustained output stops after reaching the limit, to protect the device and your current project.

What if the program is waiting for input?

Before running, use the console input button to fill in the text that will be provided to scanf or getchar, then run the code again.

How to understand diagnostics?

Start by checking the line number, column number, and description of the first error. Fix it and run again; subsequent errors are sometimes only caused by the preceding syntax issue.

Does learning progress sync?

No. Chapter completion status is only stored in the app container on the current device. No account is required, and it is not uploaded or synced via the cloud.

Can the app be used offline?

Lessons, exercises, project editing, and the educational interpreter execution do not depend on remote compilation services. Loading, purchasing, or restoring App Store products requires a connection to Apple services; if you actively select files from a cloud file provider, the system file service may also require a network connection.

Projects, Data, and File Import

Source code, project settings, learning progress, and free usage counts are stored only in the app container by default.
The app does not require an account, does not integrate advertising or third-party analytics SDKs, and does not collect or upload user code.
The app reads .c or text files you specifically select only when you actively open the system file picker.
The maximum size of a single imported file is 256 KiB; text content is supported, and binary files are not accepted.
The share button in the editor can export the current source file through the system interface.
Deleting a project removes the corresponding copy stored inside the app; deleting the app generally removes its local container data.

Interpreter Support Scope

Currently Supported

int, double, char, strings, common expressions, one-dimensional arrays, conditionals and loops, user-defined functions, return values, recursion, as well as printf, puts, putchar, scanf, getchar, and a whitelist of header declarations.

Currently Limited or Unsupported

Full ISO C toolchain, arbitrary system headers, generalized pointer arithmetic, real file I/O, networking, processes, system commands, iOS APIs, and the generation and execution of native executable files, object files, or dynamic libraries. Some lessons cover advanced concepts that cannot yet be executed in the mobile educational interpreter.

Safety Boundary

Source code is processed only by the app’s built-in interpreter; it does not use JIT and does not generate native code. User programs cannot access device files, network, contacts, photos, location, or other app data on their own.

When Import Fails

Confirm that you selected a regular .c or text file, not a folder, archive, or executable file.
Confirm that the file does not exceed 256 KiB and uses UTF-8 or common UTF-16 text encoding.
If the file is from a third-party file provider, wait for the system to complete the download and then select it again.
Importing only copies the source code to an app local project; it does not modify the original file.

Free Allowance and Permanent Unlock

Each user can run code 20 times for free and open lesson details 10 times for free. After reaching either allowance, you can purchase the non-consumable permanent unlock for unlimited continued use; this is not a subscription and will not auto-renew. The actual price and currency are provided by the App Store based on the user’s region.

How to Restore Purchases?

Open the permanent unlock page inside the app and tap “Restore Purchases.” The system may ask you to sign in with the Apple account used for the purchase. The app calls Apple’s restoration mechanism and only accepts verified current entitlements.

Contact Support

If the issue remains unresolved, please contact us through the developer contact information listed on the App Store product page. It is recommended to include the app version, device and iOS version, steps to reproduce, and a diagnostic screenshot or minimal example source code that does not contain personal information.