What Does \'Default\' Do After Class Function Declarations in C 11?

Understanding the Role of Default in Class Function Declarations

In C 11, the term "default" has gained significance in class function declarations. Understanding its meaning empowers programmers to effectively utilize the compiler-generated functions provided by the language.

What Does "Default" Do After Class Function Declarations?

The keyword "default" signifies that the compiler should generate the corresponding function for the class. As opposed to manually specifying a function body, "default" instructs the compiler to handle the function's implementation automatically. This simplifies the programming process and ensures adherence to language conventions.

Examples of Default Usage

Consider the following code snippet:

<code class="cpp">class C {
  C(const C&) = default;
  C(C&&) = default;
  C& operator=(const C&) & = default;
  C& operator=(C&&) & = default;
  virtual ~C() { }
};</code>

Here, "default" is employed for constructing copy and move constructors, as well as assignment operators. By default, C 11 generates these functions implicitly. However, if explicitly specified using "default," programmers can override the default behavior.

Benefits of Using Default

Utilizing "default" offers several benefits:

• Simplify Class Definition: It eliminates the need for verbose function declarations and implementations.
• Ensure Consistency: Default functions adhere to C 11 conventions, reducing the likelihood of errors.
• Facilitate Debugging: It minimizes the number of lines to examine, facilitating debugging efforts.

Alternatives to Default

Besides "default," programmers can also use "delete" to prevent the compiler from generating a function. This is useful when a specific function is not required or conflicts with user-defined logic.

Conclusion

The "default" keyword in class function declarations provides a concise and convenient way to leverage compiler-generated functions. It simplifies class definition, guarantees consistency, and aids in debugging tasks. Understanding default's significance empowers programmers to effectively utilize C 11 language features.

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