The following postfix expression with single-digit operands is evaluated using…
2016
The following postfix expression with single-digit operands is evaluated using a stack:
8 2 3 ^ / 2 3 * + 5 1 * -
Note that ^ is the exponentiation operator. The top two elements of the stack after the first * are evaluated are
- A.
6,1
- B.
5,7
- C.
3,2
- D.
1,5
Attempted by 336 students.
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Correct answer: A
To evaluate the postfix expression 823 ^ / 23 * + 51 * -, we use a stack. First, push operands: 8, 2, 3. Encounter ^ (exponentiation): pop 3 and 2, compute 2^3 = 8. Stack becomes [8, 8]. Next is /: pop 8 and 8, compute 8/8 = 1. Stack becomes [1]. Push next operands: 2, 3. Now encounter the first *: pop 3 and 2, compute 2*3 = 6. The stack now contains [1, 6]. Since the question asks for the top two elements after this operation, they are 6 (top) and 1 (below). Thus, the answer is '6,1'. Option A matches this result. Other options like B (5,7) or C (3,2) are incorrect because they do not reflect the actual stack state after evaluating 2*3.
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