Code Beautifier (C, C++, C#, Java, PHP, Go, Rust, Kotlin, Swift, Dart)

Code pasted from a forum, an email or an old project often arrives with mixed tabs and spaces, braces in random places and everything on one line. This beautifier re-indents C, C++, C#, Java, PHP, Go, Rust, Kotlin, Swift and Dart by their brace structure: it knows each language's strings (raw strings, verbatim strings, text blocks, interpolation), character literals and comments, so a { inside a string never shifts the indentation. Choose K&R or Allman braces, 2 or 4 spaces or tabs, how switch cases are indented, and whether each statement gets its own line.

How to use this tool

1. Paste the code and choose its language.
2. Pick the indentation (2 spaces, 4 spaces or tabs) and the brace style.
3. Choose how case labels sit inside a switch and whether to split statements onto their own lines.
4. Copy the formatted code.

Formula

indent of a line = indent unit × (open { blocks + open ( [ lines) at its start, after any leading } ) ]

Brackets inside strings, character literals and comments are ignored. A line that starts with a closing bracket is dedented before it is printed. Inside a switch, case labels get one level (or none, the Go and Swift convention) and the statements under them one more. Brackets opened on the same line count once, so foo(() => { indents its body by one level.

Example

In the sample C program the K&R setting pulls { up after main(…), the body gets 4 spaces, for( becomes for ( and ){ becomes ) {. Inside the switch, case 'a': total+=1;break; is split so that break; gets its own line under the case, and the { in case '{': and in the printf string are correctly ignored. The 17 messy lines come out as 17 evenly indented ones.