CLion 2023.1 Help

Extract function

The following demo illustrates the usage of the Extract function refactoring, as well as Extract parameter, Extract lambda parameter, and Live templates:

When the Extract Function refactoring is invoked, CLion analyses the selected block of code and detects variables that are the input for the selected code fragment and the variables that are output for it.

The detected output variable is used as a return value for the extracted function.

Extract a function

  1. In the editor, select a block of code to be transformed into a function.

  2. From the main menu or from the context menu of the selection, choose Refactor | Extract/Introduce | Method or press Control+Alt+M.

    Extract method dialog
  3. In the Extract Function dialog that opens, specify the name of the new function.

  4. Specify the return type of the function.

  5. If the function has not been yet declared, select the declaration place: above or below current place.

  6. In the parameters pane:

    • Add the new parameters or delete the unnecessary ones

    • Rename parameters or/and change their types by clicking the corresponding parameter lines and entering the new names and types

    • Reorder parameters in the list

    • Change the return type of the function

  7. You can make a function constexpr or noexcept using the corresponding checkboxes.

  8. Check the result in the Signature Preview pane and click Extract to create the function.

    The selected code fragment will be replaced with a function call.

C++ Example



int main() { int x = 15; int y = 10; int z = x - y; return 0; }
int main() { int x = 10; int y = 15; int z = XSubY(x,y); return 0; } void XSubY(int x, int y) { return x - y; }
Last modified: 12 April 2023