C Code Formatter & Beautifier

Debugging a segfault in a 200-line C function with inconsistent indentation, deeply nested if/else chains, and pointer declarations scattered across the file. Before you can trace the logic, you need to see the block structure clearly — which } matches which {, and how deeply nested you are.

What Is a C Formatter?

A C code formatter takes C source code with inconsistent spacing, indentation, or brace placement and restructures it into a clean, readable format. It aligns pointer declarations, normalizes spacing around operators, applies consistent brace placement, and properly indents nested blocks. Whether you’re working with embedded systems code, Linux kernel patches, or university assignments, a C formatter reveals the program’s structure.

This tool supports:

• 2-space, 4-space, or tab indentation — match your project’s style
• K&R or Allman brace style — opening brace on the same line or on its own line
• Pointer alignment — int *ptr, int* ptr, or int * ptr
• Consistent operator spacing — spaces around =, ==, &&, ||, <<, >>

C Formatting Styles

C has several well-established formatting styles, each with different brace placement:

K&R style (Kernighan & Ritchie): Opening brace at the end of the control statement line. Used by the Linux kernel, most C textbooks, and the original C programming language book.

Allman style (BSD): Opening brace on its own line, aligned with the control statement. Common in Windows C/C++ development and many open-source projects.

GNU style: Braces on their own line, indented two spaces from the enclosing block. Functions have braces at column zero. Used by GNU project code.

Whichever style you use, consistency within a project matters more than which style you choose.

Common Use Cases

Embedded systems code review: Embedded C code often prioritizes compact formatting for small screens. Format it with proper indentation before reviewing complex state machines or interrupt handlers.

Reading legacy codebases: Older C codebases (Linux kernel modules, POSIX utilities, database engines) may have formatting from decades of different contributors. Reformat locally to understand the structure.

Learning C: Properly formatted C code makes pointer arithmetic, memory management patterns, and control flow immediately visible to beginners.

Preparing code for documentation: Format C code snippets before including them in technical documentation, blog posts, or README files.

Frequently Asked Questions

Does this formatter handle preprocessor directives? Yes. Preprocessor directives (#include, #define, #ifdef, #pragma) are preserved at column zero (or indented if nested #if blocks are used) and do not interfere with the indentation of surrounding code.

Can it format C99 and C11 features? Yes. C99 features like designated initializers ({.x = 1, .y = 2}), variable-length arrays, _Bool, and // comments are handled. C11 features like _Generic and _Static_assert are also supported.

Does it handle function pointer declarations? Yes. Complex declarations like void (*signal(int sig, void (*handler)(int)))(int) are preserved with proper spacing. The formatter does not change the declaration syntax, only the surrounding whitespace and indentation.

Is my C code sent to a server? No. All formatting runs entirely in your browser using JavaScript. No source code is transmitted anywhere. Your code never leaves your device.