Generics exercises

First challenge

Add a myFilter(_:) method to your Stack structure. It should take a single argument, a closure that takes an Element and returns a Bool, and return a new Stack<Element> that contains any elements for which the closure returns true.

Second challenge

Write a generic function called findAll(_:_:) that takes an array of any type T that conforms to the Equatable protocol and a single element (also of type T). findAll(_:_:) should return an array of integers corresponding to every location where the element was found in the array.

Example

let positions = findAll([5,3,7,3,9], 3)

print(positions) // Should print [1, 3] to the console

Try your function with both integers and strings.

Third challenge (optional)

Modify the findAll(_:_:) function you wrote for the second challenge to accept a generic Collection instead of an array.

Note

You will need to change the return type from [Int] to an array of an associated type of the Collection protocol.