Consider the following postfix expression with single digit operands : \(6 \;…
2018
Consider the following postfix expression with single digit operands :
\(6 \; 2 \: 3 \: ^* \: / \: 4 \: 2 \: ^* \; + \: 6 \: 8 \: ^* \: -\)
The top two elements of the stack after the second ∗ is evaluated, are :
- A.
8,2
- B.
8,1
- C.
6,2
- D.
6,3
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Correct answer: B
Evaluation of the postfix expression 623*/42*+68*- to find the stack state after the second multiplication:
1. Scan 6, 2, 3: Push them onto the stack. Stack: [6, 2, 3]
2. Scan first '*': Pop 3 and 2. Calculate 2 x 3 = 6. Push 6. Stack: [6, 6]
3. Scan '/': Pop 6 and 6. Calculate 6 / 6 = 1. Push 1. Stack: [1]
4. Scan 4, 2: Push them onto the stack. Stack: [1, 4, 2]
5. Scan second '*': Pop 2 and 4. Calculate 4 x 2 = 8. Push 8. Stack: [1, 8]
After the second * is evaluated, the top element is 8 and the element below it is 1. Therefore, the top two elements are 8, 1.
Correct Option: (c) 8, 1
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