Create and manage threads of execution with std::thread.
The `std::thread` class, found in the `<thread>` header, is the primary way to create and manage threads in modern C++. A thread is an independent path of execution within a program. When a C++ program starts, it has one main thread that executes the `main` function. You can create additional threads to perform tasks concurrently. To create a new thread, you construct a `std::thread` object, passing it a callable entity (like a function pointer, a function object, or a lambda expression) and any arguments that the function needs. For example, `std::thread myThread(myFunction, arg1);` creates a new thread that immediately starts executing `myFunction` with the argument `arg1`. The original thread (e.g., the main thread) continues its own execution in parallel. A crucial aspect of thread management is joining. When you call the `.join()` method on a `std::thread` object (`myThread.join();`), the calling thread will pause and wait until `myThread` has finished its execution. It's essential to `join` with a thread (or detach it) before the `std::thread` object is destroyed. Failing to do so will cause the program to terminate. Joining ensures that all work started in a thread is completed before the program proceeds or exits, and it's the standard way to synchronize the completion of a task.