Swift is a type-safe language. Whenever we work with types, we need to specify them. For instance, a function can have specific parameters and return types. We cannot pass any types but the ones that are specified. What if we need a function that can handle more than one type?
We already know that Swift provides Any and AnyObject, but it is not good practice to use them unless we have to. Using Any and AnyObject will make our code fragile as we will not be able to catch type mismatching during compile time. Generics are the solution to our problem. Let's examine an example first. The following function simply swaps two values (a and b). The values a and b are of the Int type. We should pass only Int values to this function to be able to compile the application:
func swapTwoValues(a: inout Int, b: inout Int) {
let tempA = a
a = b
b = tempA
} Type safety is supposed to be a good thing, but it makes our code less generic...