func PrintEvenAfter (_ A:[Int]) {

 var first = true
 var prev = 0
 for i in A {
  if !first && i%2==0 {
   print (prev)
  }
  first = false
  prev = i
}

                                                9
4 9 8 5 5

first false

prev 5

UNSTRUCTURED PROGRAMMING (conditional and unconditional branching)

10 GOTO 500
30 IF X=7 GOTO 4590


ITERATIVE BLOCK PROGRAMMING / STRUCTURED PROGRAMMING

A program is divided into methods.
Methods have "blocks":  "conditionals" (if/then/else) or "loops" (while for do)

OBJECT ORIENTED PROGRAMMING

Programs make use of "objects":  collections of both methods and data
You can use objects for reasons of organization or for group work.

Why you should learn objects:  Objects provide inheritance.  And inheritance provides method overriding.

Just as when you write a method, you can give a method parameters so that a user can put any information they want into those parameters.  So that your method can solve a problem that you
the programmer are aware needs to be solved.

With object-oriented design, you can write your program to call a method--EVEN IF YOU THE PROGRAMMER DO NOT KNOW WHAT THAT METHOD IS GOING TO BE.

...
fred->report()
...

What is the report method?  There might be more than one method called report.  The first time the code is run, it might call one report method; the next time it might a call a different report method.  You the programmer do not know for sure which method will be run at the time
you write the program.