Iteratoren
Operator overloading is implemented via traits in std::ops
:
Speaker Notes
This slide should take about 5 minutes.
Discussion points:
- You could implement
Add
for&Point
. In which situations is that useful?- Answer:
Add:add
consumesself
. If typeT
for which you are overloading the operator is notCopy
, you should consider overloading the operator for&T
as well. This avoids unnecessary cloning on the call site.
- Answer:
- Why is
Output
an associated type? Could it be made a type parameter of the method?- Short answer: Function type parameters are controlled by the caller, but associated types (like
Output
) are controlled by the implementer of a trait.
- Short answer: Function type parameters are controlled by the caller, but associated types (like
- You could implement
Add
for two different types, e.g.impl Add<(i32, i32)> for Point
would add a tuple to aPoint
.
The Not
trait (!
operator) is notable because it does not "boolify" like the same operator in C-family languages; instead, for integer types it negates each bit of the number, which arithmetically is equivalent to subtracting it from -1: !5 == -6
.