Inline functions in C++ are a type of compiler optimization. When you declare a function as inline, you suggest to the compiler that it should insert the code of that function directly into the caller's code, avoiding the overhead of a regular function call. This can lead to better performance in some cases.

Emily should use a For Loop to calculate the factorial of a number. A For Loop is well-suited for tasks where you know in advance how many iterations are required, as is the case with factorial calculations. She can initialize the loop variable, set the loop condition to run until the variable reaches 1, and decrement the variable in each iteration to multiply the numbers in a descending order.

The "==" operator in C++ is the equality operator, and it is used to check if two operands are equal. It returns true if the operands are equal and false otherwise. This operator is frequently used in conditional statements and comparisons in C++ programs.

In C++, the string data type is used to store a sequence of characters, such as words or sentences. It provides convenient methods for working with text data, unlike other data types like char or int.

When an inline function is too long or complex, it can lead to increased code size. This is because the function's code is inserted at each call site, potentially resulting in larger compiled code. However, this may be offset by improved performance due to reduced function call overhead.

In C++, when a return type is not explicitly provided for a function, it defaults to 'void.' This means the function does not return a value. It's essential when you have functions that perform actions without returning a result, such as void functions for input/output or setting variables.

Functions in C++ can return multiple values using tuples. A tuple is an ordered collection of elements, and it's an excellent way to return multiple values from a function. It's more flexible than returning values using pointers, references, or arrays, as it allows you to return values of different types. Tuples were introduced in C++11.

In C++, the 'typedef' keyword is used to define user-defined data types. It allows you to create aliases for existing data types, making your code more readable and maintainable.

The loop that first checks the condition and then executes its body is called a "for loop." In a for loop, you specify the initialization, condition, and increment or decrement all within the loop header. This allows for precise control over loop execution.

In C++, the function prototype specifies the return type and the types of parameters a function expects. It provides a declaration of the function's signature, allowing the compiler to check for correct usage throughout the code.