In order to improve the configuration of files such as c_cpp_properties.json, launch.json, and tasks.json, you should use the predefined variables.

Assuming that you have:

• The directory that you open with “Open with VS Code”: /home/your-username/your-project
• The file opened in your editor: /home/your-username/your-project/folder/file.ext

The meaning of each predefined variables is:

• ${workspaceFolder} - /home/your-username/your-project
• ${workspaceFolderBaseName} - your-project
• ${file} - /home/your-username/your-project/folder/file.ext
• ${relativeFile} - folder/file.ext
• ${fileBasename} - file.ext
• ${fileBasenameNoExtension} - file
• ${fileDirname} - /home/your-username/your-project/folder
• ${fileExtname} - .ext
• ${lineNumber} - 5
• ${selectedText} - Text selected in your code editor

Refer:

https://code.visualstudio.com/docs/editor/variables-reference