Auto-import

When you reference a symbol that has not yet been imported, CLion helps you to locate the file (header, as a rule) which contains declaration (definition) of that symbol and adds it to the list of includes.

The import statement is added to the imports section, but the caret does not move from the current position, and your current editing session does not suspend. This feature is known as the Import Assistant.

Configure auto-import

You can configure the auto-import behavior for C/C++ and other languages in Settings | Editor | General | Auto Import.

Show import popup	Suggest creating imports for symbols that lack import statements (enabled by default).
Auto import in completion	Automatically insert an import statement during code completion (enabled by default).
Auto import local files with quotes	Silently add #include directives for project files (enabled by default).
Sort includes	Sort the inserted include-s according to the rules specified in .clang-format.