Question

Explain the programming steps necessary to make a class's member variable static.

Short answer

Question: Explain the steps necessary to create a static member variable in a C++ class and how to access it. Answer: To create a static member variable in a C++ class and access it, follow these 4 steps: 1. Define the class: Start by defining the class within which the static member variable will be created. For example, create a class named "ExampleClass". 2. Declare the member variable as static: Inside the class definition, declare the member variable and add the keyword "static" before the variable's type. This will define the variable as a static member variable of the class. 3. Define the static member variable outside the class: All static member variables must be defined outside the class definition because their memory is shared among all instances of a class. To define the static member variable, state its type, use the scope resolution operator (::) followed by the variable name, and assign it a value if needed. 4. Access the static member variable: To access the static member variable from outside the class, use the scope resolution operator (::) with the class name and variable name. No object instance is required to access a static member.

Step-by-step solution

Define the class

Start by defining the class within which the static member variable will be created. Consider a simple class, named "ExampleClass", to contain the static member variable. ```cpp class ExampleClass { }; ```

Declare the member variable as static

Inside the class definition, declare the member variable and add the keyword "static" before the variable's type. This will define the variable as a static member variable of the class. ```cpp class ExampleClass { public: static int staticVar; }; ``` In this example, a static integer variable named "staticVar" has been declared inside the ExampleClass.

Define the static member variable outside the class

For all static member variables, they must be defined outside the class definition. This is because a static member variable's memory is shared among all instances of a class, so it must be allocated only once. To define the static member variable, state its type, then use the scope resolution operator (::) followed by the variable name, and finally assign it a value if needed. ```cpp int ExampleClass::staticVar = 0; // Sets initial value to 0 ```

Access the static member variable

To access the static member variable from outside the class, use the scope resolution operator (::) with the class name and variable name. No object instance is required to access a static member. ```cpp #include int main() { ExampleClass::staticVar = 10; std::cout << "The value of staticVar is: " << ExampleClass::staticVar << std::endl; return 0; } ``` In this example, the static member variable "staticVar" is accessed and modified directly from the main function. This example assumes that the given code snippets are parts of a complete C++ program with the appropriate headers (`#include`), main function, and so on.