Implementing FIFO using LIFO

Question

Looking at some algorithm exercices on the net, I found an interesting one :

How would you implement a FIFO using a LIFO ?

I tried myself but I ended up wit

Answer 1

Both LIFO and FIFO can be implemented with an array, the only difference between them is in the way tail and head pointers work. Given you start with LIFO, you can add two extra pointers that would reflect FIFO's tail and head, and then add methods to Add, Remove an so on using the FIFO pointers.

The output type would be as fast as a dedicated FIFO or LIFO type, however it would support both. You would need to use distinctive type members, like AddToStack/AddToQueue, RemoveFromStack/RemoveFromQueue etc.