mutator function
Mutator method. In computer science, a mutator method is a method used to control changes to a variable. They are also widely known as setter methods. Often a setter is accompanied by a getter (also known as an accessor), which returns the value of the private member variable.
Mutator Methods. A mutator method is used to set a value of a private field. It follows a naming scheme prefixing the word set to the start of the method name. These methods do not have a return type and accept a parameter that is the same data type as their corresponding private field.