While the use of "goto" is generally discouraged in modern programming due to making code harder to read and maintain, there are rare cases, like breaking out of multiple nested loops or complex error handling before exceptions were widely adopted, where its use might be considered.

Function templates can increase both compilation times and the size of the binary due to multiple instantiations for different data types. One way to address these concerns is by reducing unnecessary template instantiations, making sure only required instantiations are compiled, and using techniques like explicit instantiation.

Inline functions in C++ are expanded at the place where they are called, rather than being invoked. Because of this, they cannot be virtual as the virtual mechanism relies on function calls.

A common memory leak scenario is when an exception is thrown before the memory allocated dynamically (usually with new) is deallocated. If the exception prevents a destructor or a delete statement from being reached, the memory is never released, resulting in a memory leak.

The primary purpose of enum (short for "enumeration") in C++ is to create user-defined data types where you can define a set of named integer constants. It provides a way to assign names to integral constants, which makes a program easier to read and maintain.

Encapsulation is achieved by bundling data (variables) and methods that operate on the data into a single unit (class) and restricting the direct access to some of the object's components. In C++, this is implemented by declaring variables as private and providing public methods (API) to access and manipulate them.

The bitwise OR operation works by comparing each bit position of the two numbers. If at least one bit is set (1) in a given position in either of the numbers, the resulting bit will be set. For 1101 OR 1010, the result is 1111.

Passing parameters by reference allows for direct access to the original memory location, eliminating the need for copying data. This reduces memory overhead and can enhance the performance of the program. While options 2 and 3 can also be benefits of passing by reference, the primary advantage is the reduction of memory usage.

The catch block in C++ is used to handle exceptions. When an exception occurs in the try block, it is passed to the catch block where it can be handled. The type of exception that a particular catch block can handle is determined by the parameter it carries.

A while loop continues execution as long as the condition within the parentheses is true. By using "while(1)", where 1 stands for true in the context of the loop's condition, it creates an infinite loop.