As mentioned in Exercise C-5.8, postfix notation is an unambiguous way of writing an arithmetic expression without parentheses. It is defined so that if “(exp₁) ◦(exp₂)” is a normal (infix) fully parenthesized expression with operation “◦,” then its postfix equivalent is “pexp₁ pexp₂◦,” where pexp₁ is the postfix version of exp₁ and pexp₂ is the postfix version of exp₂. The postfix version of a single number of variables is just that number or variable. So, for example, the postfix version of the infix expression “((5+2)∗(8−3))/4” is “5 2 + 8 3 − ∗ 4 /.” Give an efficient algorithm, that when given an expression tree, outputs the expression in postfix notation.

Data from in Exercise C-5.8

Postfix notation is an unambiguous way of writing an arithmetic expression without parentheses. It is defined so that if “(exp₁) ◦ (exp₂)” is a normal fully parenthesized expression whose operation is “◦”, then the postfix version of this is “pexp₁ pexp₂◦”, where pexp₁ is the postfix version of exp₁ and pexp₂ is the postfix version of exp₂. The postfix version of a single number or variable is just that number or variable. So, for example, the postfix version of “((5+2) ∗ (8−3))/4” is “5 2 + 8 3 − ∗ 4 /”. Describe a nonrecursive way of evaluating an expression in postfix notation.