如何在xcode中以编程方式向按钮添加操作

I know how to add an IBAction to a button by dragging from the interface builder, but I want to add the action programmatically to save time and to avoid switching back and forth constantly. The solution is probably really simple, but I just can't seem to find any answers when I search it. Thank you!I know how to add an IBAction to a button by dr