#includeIn this example, we include the `atlstr.h` header file, which is part of the Microsoft Active Template Library (ATL), and is where the `CString` class is defined. We then create a `CString` object called `myString` and assign it the value "Hello, World!". We then call the `MakeUpper` function on `myString` to convert it to all uppercase letters. Finally, we output the resulting string to the console with the `std::cout` function. The package library for this function is the "ATL" library, which is a component of the Microsoft Visual C++ runtime.#include int main() { CString myString = "Hello, World!"; myString.MakeUpper(); std::cout << myString; return 0; }