Exponentiation of negative real
d, exponentiation, real-datatype
Solution
Disclaimer: I don't know D. This is written with my background using other languages.
When you square a negitive (real) number, the number becomes positive. You are writing the ambiguous (to humans) expression:
-3^2
Which could mean either:
- `-(3^2) = -9` or
- `(-3)^2 = 9`
Judging from the output, I assume that the programming language's operator precedence is picking the first. Try replacing your last line with:
writeln((-3.0L) ^^ 2.0L); // -9
Problem
Can somebody explain why I'm getting a positive result in the first case and a negative in the second. ``` auto r1 = -3.0L; auto r2 = 2.0L; writeln(typeid(r1)); // real writeln(typeid(r2)); // real writeln(typeid(r1 ^^ r2)); // real writeln(r1 ^^ r2); // 9 writeln(typeid(-3.0L)); // real writeln(typeid(2.0L)); // real writeln(typeid(-3.0L ^^ 2.0L)); // real writeln(-3.0L ^^ 2.0L); // -9 ```