Which keyword is used to declare a method within a class in ABAP?

In ABAP, the keyword used to declare a method within a class is "METHOD." This keyword specifically identifies a method as part of a class definition, which allows for object-oriented programming paradigms to be applied. Methods in ABAP are used to define the behavior of an object, encapsulating functionality that can be executed when the object is utilized.

When you declare a method using the "METHOD" keyword in a class, you follow the structure necessary for defining the method's interface and implementation. This allows the method to operate with the attributes of the class and to be invoked on instances of that class. The proper use of the "METHOD" keyword is essential for creating organized and reusable code in ABAP.

The other keywords provided do not serve the purpose of declaring methods within a class in ABAP. "FUNCTION" is typically used in the context of standalone function modules, "PROCEDURE" is not used in ABAP for class methods, and "ROUTINE" refers to legacy terminology that is not applicable in the context of modern ABAP class definitions. Thus, the precision of using "METHOD" underscores its significance in object-oriented programming within the ABAP environment.