Unary Negative and Positive
As unary operations have only one operand they are evaluated before other operations containing them. Here is an example using negation:
- 3 − −2
Here the first '−' represents the binary subtraction operation, while the second '−' represents the unary negation of the 2. Therefore, the expression is equal to:
- 3 − (−2) = 5
Technically there is also a unary positive but it is not needed since we assume a value to be positive:
- (+2) = 2
Unary positive does not change the sign of a negative operation:
- (+(−2)) = (−2)
In this case a unary negative is needed to change the sign:
- (−(−2)) = (+2)
Unary operators (called "monadic" in APL) are also used in programming languages.
Read more about this topic: Unary Operation
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