Question

What is an accessor method? What is a mutator method?

Short answer

Answer: Accessor methods, also known as "getter" methods, are methods that allow users to access (get) the values of an object's attributes without directly accessing the attributes themselves. They are used to retrieve the value of a private attribute while ensuring the object's internal state remains consistent. Mutator methods, also known as "setter" methods, are methods that allow users to modify (set or change) the values of an object's attributes without directly accessing the attributes themselves. They are used to set or update the value of a private attribute while ensuring the object's internal state remains consistent and its integrity is maintained.

Step-by-step solution

Definition: Accessor Method

Accessor methods are methods in object-oriented programming that allow users to access (get) the values of an object's attributes without directly accessing the attributes themselves. They are also known as "getter" methods. These methods are typically used to retrieve the value of a private attribute while ensuring that the object's internal state remains consistent.

Example: Accessor Method

Suppose we have a class named "Circle" with a private attribute "radius". We can use an accessor method to get the value of the radius without the user directly accessing it. The code would look like this (in Java): class Circle { private double radius; public Circle(double radius) { this.radius = radius; } public double getRadius() { return this.radius; } } In this example, the accessor method "getRadius()" returns the value of the radius attribute.

Definition: Mutator Method

Mutator methods are methods in object-oriented programming that allow users to modify (set or change) the values of an object's attributes without directly accessing the attributes themselves. They are also known as "setter" methods. These methods are used to set or update the value of a private attribute while ensuring that the object's internal state remains consistent and its integrity is maintained.

Example: Mutator Method

Let's continue with the same "Circle" class example. We can use a mutator method to set the value of the radius without the user directly accessing it. The code would look like this (in Java): class Circle { private double radius; public Circle(double radius) { this.radius = radius; } public double getRadius() { return this.radius; } public void setRadius(double newRadius) { if (newRadius >= 0) { this.radius = newRadius; } else { System.out.println("Invalid radius value. Radius must be a non-negative value."); } } } In this example, the mutator method "setRadius(double newRadius)" sets the value of the radius attribute if the input value is non-negative, otherwise, it shows an error message.