This is a small example if how to use the shunting yard algorithm to convert expressions written using infix notation to postfix notation (aka Reverse Polish Notation, or RPN).
More information here: https://en.wikipedia.org/wiki/Shunting-yard_algorithm
Example of infix to postfix:
Infix: 2 / 8 - 3 * (15 / 5) ^ 3
Postfix: 2, 8, /, 3, 15, 5, /, 3, ^, *, -
The project also contains an evaluator that performs evaluation of the expression.
Example run:
Expression: 2 / 8 - 3 * (15 / 5) ^ 3
Infix tokens: [2, /, 8, -, 3, *, (, 15, /, 5, ), ^, 3]
Postfix tokens: [2, 8, /, 3, 15, 5, /, 3, ^, *, -]
Result: -80.75
Implemented using a Stack and a Queue to stay close to the original algorithm.
100% test coverage because why not. 😎
- Parentheses
- Exponents
- Multiplication
- Division
- Addition
- Subtraction
- Only handles integers as input
- No support for unary operations
- Doesn't handle non-integer exponents, like
9 ^ (2 / 6) - Error handling is minimal at best
PR:s are more than welcome.