- 2069 Bhadra · 5 marks
Evaluate postfix expression 574-*8/4+
Short answer
Step-by-step evaluation: push 5,7,4; 7-4=3; 5*3=15; 15/8=1.875; 1.875+4=5.875. Final value: 5.875.
Evaluate the following postfix expression showing stack after every step in tabular form: 574-*8/4+
Rule: scan left to right; a digit is an operand and is pushed; an operator pops two values (the first popped is the right operand), applies the operation and pushes the result. Each digit is a separate one-digit operand.
| Step | Symbol | Action | Stack (bottom → top) |
|---|---|---|---|
| 1 | 5 | push 5 | 5 |
| 2 | 7 | push 7 | 5, 7 |
| 3 | 4 | push 4 | 5, 7, 4 |
| 4 | - | pop 4 (right), 7 (left); 7 - 4 = 3; push | 5, 3 |
| 5 | * | pop 3 (right), 5 (left); 5 * 3 = 15; push | 15 |
| 6 | 8 | push 8 | 15, 8 |
| 7 | / | pop 8 (right), 15 (left); 15 / 8 = 1.875; push | 1.875 |
| 8 | 4 | push 4 | 1.875, 4 |
| 9 | + | pop 4 (right), 1.875 (left); 1.875 + 4 = 5.875; push | 5.875 |
Answer: 5.875 (using real division: 5 × 3 = 15, 15 / 8 = 1.875, 1.875 + 4 = 5.875). With integer division, 15 / 8 = 1 and the result is 5. Infix form: 5 * (7 − 4) / 8 + 4.
✓ Answer checked by Claude Opus 5.5 (high effort)
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