Calculator is a simple text-based calculator app made in Java. It features the basic arithmetic operators, as well as a few trigonometric and logarithmic functions.
Composed of real numbers which fit within the bounds of an 8-byte double variable.
Syntax: <expression> <operator> <expression>
| Operation | Symbol | Example |
|---|---|---|
| Addition | + | 1 + 2 = 3 |
| Subtraction | - | 2 - 3 = -1 |
| Multiplication | * | 2 * 3 = 6 |
| Division | / | 4 / 2 = 2 |
| Exponentiation | ^ | 2 ^ 3 = 8 |
Negation syntax: <operator> <expression>
Function syntax: <operator> (<expression>)
| Operation | Symbol | Example |
|---|---|---|
| Negation | - | -1 + 3 = 2 |
| Sine | sin() | sin(30) = ½ |
| Cosine | cos() | cos(90) = 0 |
| Tangent | tan() | tan(45) = 1 |
| Cotangent | cot() | cot(90) = 0 |
| Natural log (loge) | ln() | ln(e) = 1 |
| Decimal log (log10) | log() | log(100) = 2 |
Note: these mathematical functions are considered unary operators because they require only one term as input.
Syntax: (<expression>)
Use parentheses to elevate the evaluation precedence of an expression or sub-expression.
Executable calculator-1.0.jar file is located in \target directory.
With command-line argument:
java -jar calculator-1.0.jar "(12-(2^2)*2)/-4"
-1
java -jar calculator-1.0.jar "2+4-(12/-3)"
10
java -jar calculator-1.0.jar "(1+(2+3)"
[Error] Mismatched parenthesis.
Without command-line argument:
java -jar calculator-1.0.jar
Welcome to Eli's Text-based Calculator v1.0
Supported operations: +, -, *, /, ^, sin(), cos(), tan(), cot(), ln(), log().
Type "EXIT" to exit the app.
>> (12-(2^2)*2)/-4
-1
>> 2+4-(12/-3)
10
>> (1+(2+3)
[Error] Mismatched parenthesis.
>> EXIT
- Each operator must be used with its respective number of operands.
- eg. The expression "10/5" is valid, but "/5" is missing its left operand.
- No mismatched grouping parentheses; each '(' requires a matching ')'.
- Function-call parentheses are mandatory.
- Trigonometric function arguments are in degrees.
- Spaces are optional and have no effect on expression evaluation.
exp4j library
- implementation of Dijkstra's Shunting Yard Algorithm
- Token class & its utilities
Source: https://www.objecthunter.net/exp4j/
apache/commons/lang3/math/NumberUtils
- isParsable() and withDecimalsParsing() methods used for validating real number operands