Question

Use a stack to evaluate the following postfix expression and show the content of the stack after execution of each operation. Don’t write any code. Assume as if you are using push and pop member functions of the stack AB- CD+E*+

(where A=5, B=3, C=5, D=4, and E=2)

Answer 1

Expression is 5, 3, -, 5, 4, +, 2, *, +

SNo.	Symbol	Action taken	Stack	intermediate output
1	5	operand, push	5
2	3	operand, push	5,3
3	-	operator, pop twice		5-3=2
		Evaluate and push back	2
4	5	operand, push	2,5
5	4	operand, push	2,5,4
6	+	operator, pop twice	2	5+4=9
		Evaluate and push back	2,9
7	2	operand, push	2,9,2
8	*	operator, pop twice	2	9*2=18
		Evaluate and push back	2,18
9	+	operator, pop twice		2+18=20
		Evaluate and push back	20
10		pop all	20