1. int x = 3; if (x > 1) if (x > 2) { if (x > 3) System.out.println("one"); } else System.out.println("three"); else System.out.println("four"); Let’s think about this code. What does it do, how does it work?

2. int x = 3; if (x > 1) if (x > 2) { if (x > 3) System.out.println("one"); } else System.out.println("three"); else System.out.println("four"); x = 3 We visualize the instructions one by one. First x gets created and is assigned a value.

3. int x = 3; if (x > 1) if (x > 2) { if (x > 3) System.out.println("one"); } else System.out.println("three"); else System.out.println("four"); x > 1 x = 3 true We continue by drawing the flowchart. It will be our map as we walk the code line by line.

4. int x = 3; if (x > 1) if (x > 2) { if (x > 3) System.out.println("one"); } else System.out.println("three"); else System.out.println("four"); x > 1 x = 3 x > 2 true

5. int x = 3; if (x > 1) if (x > 2) { if (x > 3) System.out.println("one"); } else System.out.println("three"); else System.out.println("four"); x > 1 x = 3 x > 2 { true

6. int x = 3; if (x > 1) if (x > 2) { if (x > 3) System.out.println("one"); } else System.out.println("three"); else System.out.println("four"); x > 1 x = 3 x > 3 x > 2 { true

7. int x = 3; if (x > 1) if (x > 2) { if (x > 3) System.out.println("one"); } else System.out.println("three"); else System.out.println("four"); x > 1 x = 3 x > 3 x > 2 “one” { true

8. int x = 3; if (x > 1) if (x > 2) { if (x > 3) System.out.println("one"); } else System.out.println("three"); else System.out.println("four"); x > 1 x = 3 x > 3 x > 2 “one” { } true

9. int x = 3; if (x > 1) if (x > 2) { if (x > 3) System.out.println("one"); } else System.out.println("three"); else System.out.println("four"); x > 1 x = 3 x > 3 x > 2 “one” { } true

10. int x = 3; if (x > 1) if (x > 2) { if (x > 3) System.out.println("one"); } else System.out.println("three"); else System.out.println("four"); x > 1 x = 3 x > 3 x > 2 “one” { } true

11. int x = 3; if (x > 1) if (x > 2) { if (x > 3) System.out.println("one"); } else System.out.println("three"); else System.out.println("four"); x > 1 x = 3 x > 3 x > 2 “one” { } true

12. int x = 3; if (x > 1) if (x > 2) { if (x > 3) System.out.println("one"); } else System.out.println("three"); else System.out.println("four"); x > 1 x = 3 x > 3 x > 2 “three” “one” { } true

13. int x = 3; if (x > 1) if (x > 2) { if (x > 3) System.out.println("one"); } else System.out.println("three"); else System.out.println("four"); x > 1 x = 3 x > 3 x > 2 “three” “one” { } true

14. int x = 3; if (x > 1) if (x > 2) { if (x > 3) System.out.println("one"); } else System.out.println("three"); else System.out.println("four"); x > 1 x = 3 x > 3 x > 2 “three” “one” { } true

15. int x = 3; if (x > 1) if (x > 2) { if (x > 3) System.out.println("one"); } else System.out.println("three"); else System.out.println("four"); x > 1 x = 3 x > 3 x > 2 “three” “one” { } true

16. int x = 3; if (x > 1) if (x > 2) { if (x > 3) System.out.println("one"); } else System.out.println("three"); else System.out.println("four"); x > 1 x = 3 x > 3 x > 2 “three” “one” “four” { } true

17. int x = 3; if (x > 1) if (x > 2) { if (x > 3) System.out.println("one"); } else System.out.println("three"); else System.out.println("four"); x > 1 x = 3 x > 3 x > 2 “three” “one” “four” { } true

18. int x = 3; if (x > 1) if (x > 2) { if (x > 3) System.out.println("one"); } else System.out.println("three"); else System.out.println("four"); x > 1 x = 3 x > 3 x > 2 “three” “one” “four” { } The end. true

19. int x = 3; if (x > 1) if (x > 2) { if (x > 3) System.out.println("one"); } else System.out.println("three"); else System.out.println("four"); x > 1 x = 3 x > 3 x > 2 “three” “one” “four” { } The end. Nothing gets printed. true

20. int x = 3; if (x > 1) if (x > 2) { if (x > 3) System.out.println("one"); } else System.out.println("three"); else System.out.println("four"); Old problem

21. int x = 3; if (x > 1) { if (x > 2) if (x > 3) System.out.println("one"); } else System.out.println("three"); else System.out.println("four"); New problem

22. int x = 3; if (x > 1) if (x > 2) { if (x > 3) System.out.println("one"); } else System.out.println("three"); else System.out.println("four"); Old problem

23. int x = 3; if (x > 1) { if (x > 2) if (x > 3) System.out.println("one"); } else System.out.println("three"); else System.out.println("four"); New problem

24. int x = 3; if (x > 1) if (x > 2) { if (x > 3) System.out.println("one"); } else System.out.println("three"); else System.out.println("four"); Old problem

25. int x = 3; if (x > 1) { if (x > 2) if (x > 3) System.out.println("one"); } else System.out.println("three"); else System.out.println("four"); New problem

26. int x = 3; if (x > 1) { if (x > 2) if (x > 3) System.out.println("one"); } else System.out.println("three"); else System.out.println("four"); New problem else w/out if Does not compile!

27. int x = 3; if (x > 1) { if (x > 2) if (x > 3) System.out.println("one"); } else System.out.println("three"); else System.out.println("four"); New problem else w/out if Does not compile!

28. int x = 3; if (x > 1) { if (x > 2) if (x > 3) System.out.println("one"); } else System.out.println("three"); else System.out.println("four"); New problem else w/out if Does not compile! The only solution, then, is to carefully draw the flowchart!

29. int x = 3; if (x > 1) { if (x > 2) if (x > 3) System.out.println("one"); } else System.out.println("three"); else System.out.println("four"); New problem else w/out if Does not compile! The only solution, then, is to carefully draw the flowchart! On paper, or in your mind, it doesn’t matter. There really isn’t any reliable, uniform shortcut alternative to that.

30. int x = 3; if (x > 1) { if (x > 2) if (x > 3) System.out.println("one"); } else System.out.println("three"); else System.out.println("four"); New problem else w/out if Does not compile! The only solution, then, is to carefully draw the flowchart! On paper, or in your mind, it doesn’t matter. There really isn’t any reliable, uniform shortcut alternative to that.