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Built in Operators

There are three basic sets of operators available:

Arithmetic

All of the arithmetic operators are included and available: +, -, *, / and of course % (modulo).

Boolean

Boolean operators will consider false every value equal to zero (0 ± 0.000000000001), and true every other value.

But they are warrantied to return 1.0 for true and 0.0 for false. The available operators are: & (and), | (or), ¬ (not).

There are also a set of Extra Functions and Operators

Precedence

For those who don't know, precedence of operators refers to which of theoperators will be evaluated first when left alone. I won't bother you with numbers, the order of evaluation is as follows:

FIRST->  * / %  - +  ¬  &  |  == !=   <-LAST
         -----  ---  -  -  -  -----    
         ^^^ The dashes indicate groups with the same precedence

When operators have the same precedence they will be evaluated from left to right.

Note: as in primary school (and beyond) you can always alter the precedence of operators with the use of parentheses.

Factorial

Factorial isn't technically an operator... it's a function but since it's so common, it's implemented by using the ! symbol and with more precedence than the arithmetic multiplication. Even though the implementation of operators is trivial in exp4j the factorial is the only postfix unary operator, so it deserves a special case.

Note: Factorials from 0! to 21! are guaranteed to be correct, bigger than 21! may suffer lost of precision because of double rounding.
Note 2: Factorials bigger than 170! will rise an IllegalArgumentException since the value will be Double.INFINITY.

Code

The code for the operators is here.

Updated by Federico Vera over 1 year ago · 6 revisions

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