区分 C/C++ 的各个 format style

在VS Code编辑C/C++文件时，Alt+Shift+F 快捷键会默认使用拓展C/C++进行文档格式化

查看C_Cpp.formatting@ext:ms-vscode.cpptools这一配置项，发现VS Code默认使用clang-format进行格式化

Coding style, currently supports: Visual Studio, LLVM, Google, Chromium, Mozilla, WebKit, Microsoft, GNU. Use file to load the style from a .clang-format file in the current or parent directory, or use file:<path>/.clang-format to reference a specific path.

查询文档Clang-Format Style Options — Clang 20.0.0git documentation得知

• LLVM A style complying with the LLVM coding standards
• Google A style complying with Google’s C++ style guide
• Chromium A style complying with Chromium’s style guide
• Mozilla A style complying with Mozilla’s style guide
• WebKit A style complying with WebKit’s style guide
• Microsoft A style complying with Microsoft’s style guide
• GNU A style complying with the GNU coding standards

1. LLVM Style

• Indentation: 2 spaces.
• Braces: Opening braces on the same line, closing braces on their own line.
• Line Length: 80 columns.
• Naming: CamelCase for types, lower_case for functions and variables.
• Spacing: Spaces around operators, after commas, and in control structures.
• Pointer Alignment: int *ptr (space before *).
• Comments: Use // for single-line comments, /* */ for multi-line.
• Philosophy: Focus on readability and consistency, with a preference for simplicity.

2. Google Style

• Indentation: 2 spaces.
• Braces: Opening braces on the same line, closing braces on their own line.
• Line Length: 80 columns.
• Naming: CamelCase for types, snake_case for functions and variables.
• Spacing: Spaces around operators and after commas.
• Pointer Alignment: int* ptr (space after *).
• Comments: Use // for single-line comments, /* */ for multi-line.
• Philosophy: Emphasizes readability and consistency, with a focus on large-scale codebases.

3. Chromium Style

• Indentation: 2 spaces.
• Braces: Opening braces on the same line, closing braces on their own line.
• Line Length: 80 columns.
• Naming: CamelCase for types, snake_case for functions and variables.
• Spacing: Spaces around operators and after commas.
• Pointer Alignment: int* ptr (space after *).
• Comments: Use // for single-line comments, /* */ for multi-line.
• Philosophy: Similar to Google Style but with some additional restrictions for Chromium-specific code.

4. Mozilla Style

• Indentation: 2 spaces.
• Braces: Opening braces on the same line, closing braces on their own line.
• Line Length: 80 columns.
• Naming: PascalCase for types, camelCase for functions and variables.
• Spacing: Spaces around operators and after commas.
• Pointer Alignment: int* ptr (space after *).
• Comments: Use // for single-line comments, /* */ for multi-line.
• Philosophy: Focuses on readability and maintainability, with a preference for clarity.

5. WebKit Style

• Indentation: 4 spaces.
• Braces: Opening braces on the same line, closing braces on their own line.
• Line Length: 100 columns.
• Naming: PascalCase for types, camelCase for functions and variables.
• Spacing: Spaces around operators and after commas.
• Pointer Alignment: int* ptr (space after *).
• Comments: Use // for single-line comments, /* */ for multi-line.
• Philosophy: Prioritizes readability and consistency, with a focus on web-related code.

6. Microsoft Style

• Indentation: 4 spaces.
• Braces: Opening braces on their own line, closing braces on their own line (Allman style).
• Line Length: 120 columns.
• Naming: PascalCase for types, camelCase for functions and variables.
• Spacing: Spaces around operators and after commas.
• Pointer Alignment: int* ptr (space after *).
• Comments: Use // for single-line comments, /* */ for multi-line.
• Philosophy: Emphasizes clarity and maintainability, with a focus on Windows development.

7. GNU Style

• Indentation: 2 spaces (for C), 8 spaces (for C++).
• Braces: Opening braces on their own line, closing braces on their own line (Allman style).
• Line Length: 79 columns.
• Naming: snake_case for types, functions, and variables.
• Spacing: Spaces around operators and after commas.
• Pointer Alignment: int *ptr (space before *).
• Comments: Use /* */ for both single-line and multi-line comments.
• Philosophy: Focuses on simplicity and adherence to GNU standards, with a preference for readability.

Key Differences

1. Indentation:
   • LLVM, Google, Chromium, Mozilla: 2 spaces.
   • WebKit, Microsoft: 4 spaces.
   • GNU: 2 spaces (C), 8 spaces (C++).
2. Braces:
   • LLVM, Google, Chromium, Mozilla, WebKit: Opening braces on the same line.
   • Microsoft, GNU: Opening braces on their own line (Allman style).
3. Line Length:
   • LLVM, Google, Chromium, Mozilla: 80 columns.
   • WebKit: 100 columns.
   • Microsoft: 120 columns.
   • GNU: 79 columns.
4. Naming Conventions:
   • LLVM, Google, Chromium: CamelCase for types, snake_case for functions and variables.
   • Mozilla, WebKit, Microsoft: PascalCase for types, camelCase for functions and variables.
   • GNU: snake_case for everything.
5. Pointer Alignment:
   • LLVM, GNU: int *ptr (space before *).
   • Google, Chromium, Mozilla, WebKit, Microsoft: int* ptr (space after *).
6. Comments:
   • Most use // for single-line and /* */ for multi-line.
   • GNU prefers /* */ for all comments.

Similarities

• All styles emphasize readability and consistency.
• Spaces around operators and after commas are common.
• Most use // for single-line comments and /* */ for multi-line comments.
• Most styles align braces and indentation consistently.