[operation] examine first element [Ada] First_Element [Java] peekFirst [Perl] $array[0] [PHP] reset [Python] [0] [Ruby] first [JavaScript] [0] [C++] 
front
p u s h _ b a c k
p u s h _ f r o n t
p o p _ b a c k
p o p _ f r o n t
b a c k
f r o n t