C++ typically handles template instantiation on a per-translation unit basis. This means each translation unit will have its own instance of the template. Linkers are smart enough to discard duplicate instances, ensuring that only one instance remains in the final executable.

The auto keyword for automatic type deduction was introduced in C++11. It allows the compiler to automatically deduce the type of a variable based on its initializer, enhancing code readability and maintainability.

The Command Pattern encapsulates a command request as an object, allowing the parameters to be passed, queued, and executed at a later time. This makes the code modular, maintainable, and ensures decoupling between classes that invoke operations from those that perform operations.

In C++, a constructor is a special member function that is automatically called when an object is instantiated. Its primary purpose is to initialize the object's attributes.

C++ supports data hiding primarily through the use of private and protected access specifiers. Private members are strictly inaccessible from outside the class, while protected members are accessible in derived classes. This mechanism is more flexible compared to some languages that might use other strategies.

The ifstream class stands for input file stream and is primarily used for performing input operations on files. This means it is used for reading data from files, making it crucial for file handling in C++.

When a pointer is passed to a function, the function gets a copy of the pointer, which contains the memory address of the data. Therefore, the function can access and modify the original data through this memory address. This is different from passing the actual data, where the function would receive a copy of that data, and any changes wouldn't affect the original data.

The "ios::app" mode in C++ stands for "append". When a file is opened in this mode, data will be appended to the end of the file's content if it already exists. If the file does not exist, a new one is created.

The "fstream" class in C++ is suitable for both input and output operations. This means you can use it for both reading from and writing to files. In contrast, "ifstream" is specifically for input (reading) and "ofstream" is for output (writing).

The "tellg()" function in C++ is used to get the current position of the file pointer in a file when working with input operations. It returns the current position of the reading cursor within the file, which is useful for various file handling tasks.