Question

A(n) _________ member function cannot access any non-static member variables in its own class.

Short answer

Answer: Static

Step-by-step solution

Understand static and non-static member variables

In a class, member variables can be both static and non-static. Static member variables are shared among all objects of the class, and there is only one copy of the static variable in memory. Non-static member variables, on the other hand, belong to individual objects of the class, and each object has its own copy of the non-static variable.

Understand static and non-static member functions

Member functions can also be static or non-static. Static member functions can only access static member variables of the class and manipulate them. Non-static member functions can access both static and non-static member variables of the class.

Identify the type of member function that cannot access non-static member variables

Since a static member function can only access static member variables and not non-static member variables, the answer to the exercise is "static". A(n) __static__ member function cannot access any non-static member variables in its own class.

Key concepts

Member Variables

In C++, member variables are the building blocks of a class. They define the properties and data that the object, an instance of the class, will hold. Each member variable can have its own unique characteristics and attributes.

• Static Member Variables: These are shared across all instances of a class. There is only one instance of a static member variable, regardless of how many objects of the class exist. This means that if one object changes the value of a static member variable, that change is reflected across all other objects of the class. They are useful when you want to have data shared among all class objects.


• Non-static Member Variables: Each object of a class has its own set of non-static member variables. This means every time a new object is created, a new memory allocation occurs for these non-static members. They vary per instance, allowing each object to maintain its own state independently of others.

Understanding the difference between static and non-static member variables is crucial because it influences how you design your class and manage data within your class.

Class Objects

Class objects are the instances you create from a class blueprint. When you define a class, you're essentially creating a new data type. To make use of this data type, you instantiate objects.

• Instantiation: This is the process of creating specific instances from the class blueprint, using the defined structure and member variables of the class.


• Object Interaction: Objects can interact with each other and access their member variables and functions to perform designated tasks. The behavior of these interactions is largely defined by the non-static member functions.

Remember, each object will maintain its own separate state unless static member variables are involved. Understanding this helps manage how objects store data and interact with each other.

Static vs Non-static

The concept of static versus non-static is pivotal in understanding C++ classes and how they behave.

Static Members:

• Static Member Variables: Shared among all objects of the class. Changing the value in one instance affects all others.
• Static Member Functions: These can only interact with static variables. They don't have access to "this", as they are not dependent on the object's state.

Non-static Members:

• Non-static Member Variables: Unique to each object. They store data specific to the instance.
• Non-static Member Functions: Can access both static and non-static member variables. They're able to use "this" pointer to refer to the instance they belong to.

Choosing between static and non-static depends on whether you want to maintain a shared state or keep the state specific to each object. This decision impacts how member functions can interact with member variables.