Swift about closures and functions

Call function, when there is a closure parameter:

In the implementation of the function: When the closure is a parameter, there is a parameter return value type;

When a closure is called, the incoming parameter

When calling a function: The closure is the implementation of the closure, and when the closure is the last parameter, it can be written outside the parameter brackets

That is, the ===> function is implemented at the time of definition, calling the simultaneous parameter (implementation is certain, parameters are variable)

The closure is implemented as a parameter (the implementation is mutable and the parameter is fixed [when used in the same function])

Swift about closures and functions