A second year project where our group was tasked to create a calculator based on reverse polish notation.
In reverse Polish notation, the operators follow their operands; for instance, to add 3 and 4 together, one would write 3 4 + rather than 3 + 4. If there are multiple operations, operators are given immediately after their final operands (often an operator takes two operands, in which case the operator is written after the second operand); so the expression written 3 − 4 + 5 in conventional notation would be written 3 4 − 5 + in reverse Polish notation: 4 is first subtracted from 3, then 5 is added to it.
Run the program and in the console type operators and operands with a space in between each character.
| Typical input | RPN equivalent |
|---|---|
| (3 * 4) - ( 5 + 2) | 3 4 * 5 2 + - |
All binary operators have an equivalent repeating form for ease of use. For example:
| Input | Output |
|---|---|
| 1 2 3 4 +! | [10] |
| 1 2 3 4 *! | [24] |
| 1 2 3 4 -! | [-2] |
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Special operator "d" duplicates the top item of the current stack.
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Special operator "o" outputs the top item from the current stack.
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Special operator "c" is used to copy the second to last element in the stack n times where n is the number right before the "c".
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Special operator "r" is used to take the second to last element and insert it into the stack n steps behind where n is the number right before the "r".
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Parenthesis are used to repeat operations k times where k is the number ontop of the stack.
Examples:
| Input | Output |
|---|---|
| 1 3 c | [1, 1, 1] |
| 2 4 c *! | [16] |
| 1 2 3 o | 3 [1, 2, 3] |
| 1 2 3 4 2 r | [1, 2, 4, 3] |
| 1 2 3 4 4 r | [4, 1, 2, 3] |
| 1 3 ( 2 * ) | [8] |
| 1 1 1 6 ( + d 3 r ) | [21, 13, 21] |
| 1 1 10 ( d 3 r + o ) | 2 3 5 8 13 21 34 55 89 144 [89, 144] |
| 1 3 ( d 2 ( 1 + ) * ) | [255] |