Description: The extern keyword is used in C++ to declare a variable or function that is defined in another translation unit. This allows different source code files to communicate with each other, facilitating modularity and code reuse. By declaring a variable or function as extern, the compiler understands that its definition is located elsewhere, which prevents code duplication and reduces the risk of errors. This feature is fundamental in C++ programming, as it enables the creation of libraries and the organization of code across multiple files, enhancing the readability and maintainability of software. Additionally, the use of extern is essential for managing global variables and for implementing functions that need to be accessible from different parts of a program. In summary, extern is a key tool in C++ that promotes collaboration between different code modules, thereby optimizing the software development process.
