Evaluate the following postfix expression using stack in C 1 2 3 1 uparrow uparrow 4 5 6star 7star?

Answer 1

Evaluation of a postfix expression is done in the following manner:

Scan the expression from the front.

1) If it is a number then push it into the stack.

2) If it is an operator, then pop two numbers from the stack and then evaluate them using the operator and push it back into the stack.

Now consider the given expression. I have presented the sequence in which the expression will be evaluated by using braces.

Note - I am using '!' symbol for uparrow

1231!!-456*7*-

->

12(3!1)!-456*7*-

->

1(2!(3!1))-456*7*-

->

(1-(2!(3!1)))56*7*-

->

(1-(2!(3!1)))(5*6)7*-

->

((1-(2!(3!1)))-((5*6)*7))

This will be your final result.