Qu$56$: Applying the following steps to convert an input expression to an output

expression:

$(1)$ Initialize an empty stack to hold operators temporarily during the conversion process.

$(2)$ Initialize an empty list to hold the output expression.

$(3)$ Scan the infix expression from left to right, one token $($operator or operand$)$ at a time.

$(4)$ For each token, do the following:

a$.$ If it is an operand $($a number or a variable$),$ add it to the output expression list.

b$.$ If it is an operator, do the following:

i$.$ While the stack is not empty and the precedence of the operator at the

iop of the stack is greater than or equal to the precedence of the current

operator, pop operators from the stack and add them to the output

expression list.

ii$.$ Push the current operator onto the stack.

c$.$ If it is an opening parenthesis $\text{'}(\text{'},$ push it onto the stack.

d$.$ If it is a closing parenthesis $\text{'})\text{'},$ pop operators from the stack and add them to

the output expression list until an opening parenthesis is encountered. Pop and

discard the opening parenthesis.

$(5)$ After scanning the entire input expression, pop any remaining operators from the stack

and add them to the output expression list.

$(6)$ The resulting postfix expression, stored in the list, will be the equivalent expression to

the original infix expression.