int num_of_apples;
void print_hello_to(string name) { cout << "Hello, " << name << "!" << endl; }In this example, `print_hello_to` is the identifier for the function that prints "Hello, [name]!" to the console. It takes a string argument `name` and returns nothing (`void`). The C++ standard library includes several packages and libraries that use different identifiers. For example, the `iostream` library is used for input and output operations, including `cout`, `cin`, and `endl`. The `vector` package is used for creating dynamic arrays that can be resized during runtime using `push_back()` and other functions. Overall, identifiers are an essential part of C++ programming, allowing programmers to write readable and maintainable code.