IntList$()$: Initializes an empty list.

void push$\_$front$($int value$)$: Inserts a data value $($within a new node$)$ at the front end of the list.

bool empty$()$ const: Returns true if the list does not store any data values $($does not have any nodes$),$ otherwise returns false.

const int & front$()$ const: Returns a reference to the first value in the list. Calling this on an empty list causes undefined behavior.

const int & back$()$ const: Returns a reference to the last value in the list. Calling this on an empty list causes undefined behavior.

void pop$\_$front$()$: Removes the value $($actually removes the node that contains the value$)$ at the front end of the list. Does nothing if the list is already empty.

void clear$()$: Removes $($deallocates$)$ all IntNodes in the IntList. Don't forget to set both head and tail to appropriate values for an empty list. DO NOT leave them dangling!

~IntList$()$: Deallocates all remaining dynamically allocated memory $($all remaining IntNodes$).$ Once the clear function is working, this destructor just needs to call the clear function.

Global $($non$-$member$)$ Friend Function

friend ostream & operator$<<($ostream &$,$ const IntList &$)$: Overloads the insertion operator $(<<)$ so that it sends to the output stream $($ostream$)$ in a single line all of the int values stored in the list, each separated by a space. This function does NOT send a newline or space at the end of the line.