Is the concept of IMPORTING and EXPORTING parameters in ABAP the same or similar to the concept of inheritance

I want to understand the concept of Importing, Exporting and Changing parameters in ABAP, because I have never met them before. To my understanding you can pass down values of parameters from one method to another using Importing, Exporting and Changing keywords.

The concept of inheritance for classes and methods is clear to me. But it seems to me that there are some parallels between those two concepts?

Suppose I call method B from method A and I use Exporting to pass to method B a parameter value from method A. Is that „inheritance“? Is it correct to say that the method B inherited a parameter value from the method A?

The concept of inheritance has nothing to do with method parameters.

Inheritance in short allows you to derive new classes from existing classes where the new class (subclass) inherits all components of the existing class (superclass)

Methods parameters define 'the interface' of the method, how the method should be used from the outside world, i.e. what data it expects as an input and what it returns as a result. Method is a name for a function/procedure which is contained inside the class, and method name together with its parameters known as method signature.

You can call any method of any class from any metod of any class, from other types of programs, function modules, etc as long as it is formally allowed (i.e. visibility rules allow this call, an object instance is available for an instance method call, static method call using the name of the class, etc).

In ABAP it is possible to define multiple input and multiple output parameters for a method and there are several possibilities for this:

• IMPORTING in method definition defines input parameters, an appropriate actual parameter must be specified for every non-optional input parameter by method call

> when the method is called, the actual IMPORTING parameters are supplied with an
EXPORTING keyword

• EXPORTING in method definition defines output parameters, an appropriate actual parameter can be specified for every output parameter by method call
  > when method is called, the EXPORTING parameters are assigned to the actual parameters using IMPORTING keyword

• CHANGING defines input/output parameters, an appropriate actual parameter must be specified for every non-optional input/output parameter by method call. The content of the actual parameter is passed to the input/output parameter in the call and ater the class the content of the input/output parameter is passed to the actual parameter
  > when method is called, the CHANGING parameters are assigned to the actual parameters using CHANGING keyword

• RETURNING VALUE(r) in method definition defines alongside any other formal parameters, precisely one return value r
  > when method is called, the RETURNING parameter is assigned to the actual parameters using RECEIVING keyword or this (functional) method can be used in an operand position