How to use the command `astyle` (with examples)

The command astyle is a source code indenter, formatter, and beautifier for the C, C++, C# and Java programming languages. It allows you to automatically format your code according to different styles and indentation rules.

Use case 1: Apply the default style

Code:

astyle source_file

Motivation: You can use this command to apply the default style to your source code file, with 4 spaces per indent and no additional formatting changes.

Explanation: When you run the command astyle source_file, the astyle executable is invoked with the source_file as the argument. This applies the default formatting rules to the source_file. The original file is not modified, instead, a copy of the original file is created with an “.orig” appended to the original file name.

Example output: The source code file source_file will be indented with 4 spaces per indent and no additional formatting changes.

Use case 2: Apply the Java style with attached braces

Code:

astyle --style=java path/to/file

Motivation: If you are working on a Java project and want to follow the common Java coding conventions, you can use this command to apply the Java style to your code.

Explanation: By adding the argument --style=java to the astyle command, you specify that you want to apply the Java style to the code in the file located at path/to/file. The Java style includes attached braces, where opening braces are placed on the same line as the statement and closing braces are placed on a new line.

Example output: The code in the file located at path/to/file will be formatted according to the Java style, with attached braces.

Use case 3: Apply the allman style with broken braces

Code:

astyle --style=allman path/to/file

Motivation: If you prefer the Allman style, which uses broken braces where opening braces are placed on a new line and closing braces are placed on a new line, you can use this command.

Explanation: By adding the argument --style=allman to the astyle command, you specify that you want to apply the Allman style to the code in the file located at path/to/file. The Allman style includes broken braces.

Example output: The code in the file located at path/to/file will be formatted according to the Allman style, with broken braces.

Use case 4: Apply a custom indent using spaces

Code:

astyle --indent=spaces=number_of_spaces path/to/file

Motivation: If you want to apply a custom indent using spaces, you can use this command. You can choose the number of spaces for each indent.

Explanation: By adding the argument --indent=spaces=number_of_spaces to the astyle command, you specify that you want to apply a custom indent using spaces to the code in the file located at path/to/file. Replace number_of_spaces with the desired number of spaces for each indent, ranging from 2 to 20.

Example output: The code in the file located at path/to/file will be formatted with the specified number of spaces for each indent.

Use case 5: Apply a custom indent using tabs

Code:

astyle --indent=tab=number_of_tabs path/to/file

Motivation: If you prefer using tabs for indentation instead of spaces, you can use this command to apply a custom indent using tabs. You can choose the number of tabs for each indent.

Explanation: By adding the argument --indent=tab=number_of_tabs to the astyle command, you specify that you want to apply a custom indent using tabs to the code in the file located at path/to/file. Replace number_of_tabs with the desired number of tabs for each indent, ranging from 2 to 20.

Example output: The code in the file located at path/to/file will be formatted with the specified number of tabs for each indent.