nexta '+is seenso and are poppedand is pushed topofstack topofstack now is pushed next'+pops and and pushes topofstack finallya '*is seen and and are poppedthe result is pushed topofstack the time to evaluate postfix expression is ( )because processing each element in the input consists of stack operations and therefore takes constant time the algorithm to do so is very simple notice that when an expression is given in postfix notationthere is no need to know any precedence rulesthis is an obvious advantage