GATE CS 2015 Set 3 Q12 — Arrays, Stacks and Queues

To evaluate the postfix expression $10 \; 5 \; + \; 60 \; 6 \; / \; * \; 8 \; -$, we use a stack to store the operands and apply operators to the top two elements of the stack:

1. Scan 10, 5: Push both onto the stack.
   Stack: [10, 5]
2. Scan +: Pop 5 and 10. Compute $10 + 5 = 15$. Push 15.
   Stack: [15]
3. Scan 60, 6: Push both onto the stack.
   Stack: [15, 60, 6]
4. Scan /: Pop 6 and 60. Compute $60 / 6 = 10$. Push 10.
   Stack: [15, 10]
5. Scan *: Pop 10 and 15. Compute $15 \times 10 = 150$. Push 150.
   Stack: [150]
6. Scan 8: Push 8 onto the stack.
   Stack: [150, 8]
7. Scan -: Pop 8 and 150. Compute $150 - 8 = 142$. Push 142.
   Stack: [142]

Thus, the final evaluated result is 142, which corresponds to option C.