Page 508 - Computer science 868 Class 12
P. 508
OR Pop top two operands
False OR False = False False
Push False
True Push True
False
AND Pop top two operands False
False AND True = False
Push False
Pop all
Ans. False
4. Evaluate the following postfix expression. Show the status of stack after execution of each operation:
5, 2, *, 50, 5, /, 5, –, +. [CBSE All India 2013]
Symbol scanned Operation Stack Result
5 Push 5
2 Push 5, 2
* Pop 5, 2
Push 10 5*2 = 10
50 Push 10, 50
5 Push 10, 50, 5
/ Pop 10, 50, 5 50/5 = 10
Push 10, 10
5 Push 10, 10, 5
- Pop 10, 10, 5 10 - 5 = 5
Push 10, 5
+ Pop 10, 5 10 + 5 = 15
Pop all
Ans. 15
The algorithm to convert an Infix expression to its Prefix form is given below.
Step 1: Start
Step 2: Reverse the infix expression. The left parenthesis changes to right parenthesis and vice versa.
Step 3: Repeat Step 4 to step 8 by reading the reversed infix expression from left to right one element at a time.
Step 4: If the symbol scanned is an operand, append it to the postfix expression.
506506 Touchpad Computer Science-XII

