14.8. Function-Call Operator
![Image](/api/v2/epubs/9780133053043/files/graphics/core.jpg)
Classes that overload the call operator allow objects of its type to be used as if they were a function. Because such classes can also store state, they can be more flexible than ordinary functions.
As a simple example, the following struct
, named absInt
, has a call operator that returns the absolute value of its argument:
struct absInt { int operator()(int val) const { return val < 0 ? -val : val; }};
This class defines a single operation: the function-call operator. That operator takes an argument of type int
and returns the argument’s absolute value.
We use the call operator by applying an argument ...
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