1. Welcome back to Software Development!

2. Algorithm Guidelines…

3. Algorithm Guidelines…
One action per step or flowchart box:
Too many words in the step / box?
Keep it short and sweet … 5-6 words per step / box.
Conjunction Junction…
And, or, but, unless, ...
Likely more than one action in the step.
Look for buried questions or decisions
Looping words: continue, do, repeat (the flow arrows covers these)
Decision words: is, if, ?
“Keep the larger number” is a decision (if x > y) and an action (keep x)…2 steps

4. Flowcharting Recap…

5. Flowcharting Recap…
Start or end of algorithm:

6. Flowcharting Recap…
Start or end of algorithm:
Leave the house

7. Flowcharting Recap… Start or end of algorithm: Leave the house
At school - done

8. Flowcharting Recap… Start or end of algorithm: Action/process step:
Leave the house
At school - done

9. Flowcharting Recap… Start or end of algorithm: Action/process step:
Leave the house
At school - done
Start the car

10. Flowcharting Recap… Start or end of algorithm: Action/process step:
Input or output operation:
Leave the house
At school - done
Start the car

11. Flowcharting Recap… Start or end of algorithm: Action/process step:
Input or output operation:
Leave the house
At school - done
Start the car
Ask for directions

12. Flowcharting Recap… Start or end of algorithm: Action/process step:
Input or output operation:
Decision:
Leave the house
At school - done
Start the car
Ask for directions

13. Flowcharting Recap… Start or end of algorithm: Action/process step:
Input or output operation:
Decision:
Leave the house
At school - done
Start the car
Ask for directions
Is the stoplight red?
Yes No

14. “Sorting a list of numbers” Algo
See if you can find a way to use your “largest number” or “smallest number” algorithm to sort a (any) list of numbers.

15. “Sorting a list of numbers” Algo Example

16. “Sorting a list of numbers” Algo Example
Start with full list

17. “Sorting a list of numbers” Algo Example
Start with full list
Remember where start of list is

18. “Sorting a list of numbers” Algo Example
Start with full list
Remember where start of list is Do

19. “Sorting a list of numbers” Algo Example
Start with full list
Remember where start of list is Do
Run “smallest number” algorithm on list

20. “Sorting a list of numbers” Algo Example
Start with full list
Remember where start of list is Do
Run “smallest number” algorithm on list – get smallest number

21. “Sorting a list of numbers” Algo Example
Start with full list
Remember where start of list is Do
Run “smallest number” algorithm on list – get smallest number
Swap smallest number with first number in list

22. “Sorting a list of numbers” Algo Example
Start with full list
Remember where start of list is Do
Run “smallest number” algorithm on list – get smallest number
Swap smallest number with first number in list
New list starts with 2nd item

23. “Sorting a list of numbers” Algo Example
Start with full list
Remember where start of list is Do
Run “smallest number” algorithm on list – get smallest number
Swap smallest number with first number in list
New list starts with 2nd item
While new list has #’s in it

24. “Sorting a list of numbers” Algo Example
Start with full list
Remember where start of list is Do
Run “smallest number” algorithm on list – get smallest number
Swap smallest number with first number in list
New list starts with 2nd item
While new list has #’s in it
Original list is now sorted

25. Get smallest # (smallest # algo) New list starts w/2nd item
Start w/full list
Remember start of list
Get smallest # (smallest # algo)
Swap w/1st
New list starts w/2nd item
New list have #? No
Yes
Orig list is sorted

26. Loops

27. Loops
Three keys to making a loop work:

28. Loops
Three keys to making a loop work:
Getting it started right

29. Loops Three keys to making a loop work: Getting it started right
Keeping it moving along

30. Loops Three keys to making a loop work: Getting it started right
Keeping it moving along
Determining when to quit looping

31. Loops Three keys to making a loop work:
Getting it started right – initialization
Keeping it moving along
Determining when to quit looping

32. Loops Three keys to making a loop work:
Getting it started right – initialization
Keeping it moving along – iteration
Determining when to quit looping

33. Loops Three keys to making a loop work:
Getting it started right – initialization
Keeping it moving along – iteration
Determining when to quit looping – exit conditions

34. Get smallest # (smallest # algo) New list starts w/2nd item
Start w/full list
Remember start of list
Get smallest # (smallest # algo)
Swap w/1st
New list starts w/2nd item
New list have #? No
Yes
Orig list is sorted

35. Get smallest # (smallest # algo) New list starts w/2nd item
Start w/full list
Remember start of list
Get smallest # (smallest # algo)
Swap w/1st
Loop
New list starts w/2nd item
New list have #? No
Yes
Orig list is sorted

36. Get smallest # (smallest # algo) New list starts w/2nd item
Start w/full list
Initialization
Remember start of list
Get smallest # (smallest # algo)
Swap w/1st
Loop
New list starts w/2nd item
New list have #? No
Yes
Orig list is sorted

37. Get smallest # (smallest # algo) New list starts w/2nd item
Start w/full list
Initialization
Remember start of list
Get smallest # (smallest # algo)
Swap w/1st
Loop
New list starts w/2nd item
Iteration
get to next loop
New list have #? No
Yes
Orig list is sorted

38. Get smallest # (smallest # algo) New list starts w/2nd item
Start w/full list
Initialization
Remember start of list
Get smallest # (smallest # algo)
Swap w/1st
Loop
New list starts w/2nd item
Iteration
get to next loop
New list have #? No
Exit condition
Yes
Orig list is sorted

39. Loops
Boundary conditions

40. Loops
Boundary conditions
The limiting factors or conditions

41. Loops Boundary conditions
The limiting factors or conditions … the “edges”

42. Loops Boundary conditions
The limiting factors or conditions … the “edges”
Weird/strange values that you suspect may break your algorithm

43. Loops
“Largest number” boundary conditions:

44. Loops “Largest number” boundary conditions:
Having a wide range of numbers … number of digits

45. Loops “Largest number” boundary conditions:
Having a wide range of numbers … number of digits
Negative numbers

46. Loops “Largest number” boundary conditions:
Having a wide range of numbers … number of digits
Negative numbers
Zero

47. Loops “Largest number” boundary conditions:
Having a wide range of numbers … number of digits
Negative numbers
Zero
All numbers in the list the same

48. Loops “Largest number” boundary conditions:
Having a wide range of numbers … number of digits
Negative numbers
Zero
All numbers in the list the same
An extremely long list

49. Loops “Largest number” boundary conditions:
Having a wide range of numbers … number of digits
Negative numbers
Zero
All numbers in the list the same
An extremely long list
An empty list

50. Loops “Largest number” boundary conditions:
Having a wide range of numbers … number of digits
Negative numbers
Zero
All numbers in the list the same
An extremely long list
An empty list
Largest number actually the first in the list

51. Loops “Largest number” boundary conditions:
Having a wide range of numbers … number of digits
Negative numbers
Zero
All numbers in the list the same
An extremely long list
An empty list
Largest number actually the first in the list
Largest number actually the last in the list

52. Loops

53. Loops
Every

54. Loops
Every every

55. Loops
Every every every

56. Loops
Every every every every

57. Loops
Every every every every loop must have an exit

58. Loops Every every every every loop must have an exit
Any arrow going back up is a loop

59. Loops Every every every every loop must have an exit
Any arrow going back up is a loop
One of the most common causes of bugs

60. Loops Every every every every loop must have an exit
Any arrow going back up is a loop
One of the most common causes of bugs
For every loop, identify your boundary conditions

61. Loops Every every every every loop must have an exit
Any arrow going back up is a loop
One of the most common causes of bugs
For every loop, identify your boundary conditions
Then test the loop for those boundary conditions

62. Loops Every every every every loop must have an exit
Any arrow going back up is a loop
One of the most common causes of bugs
For every loop, identify your boundary conditions
Then test the loop for those boundary conditions
For every loop, identify your termination/exit conditions

63. Loops Every every every every loop must have an exit
Any arrow going back up is a loop
One of the most common causes of bugs
For every loop, identify your boundary conditions
Then test the loop for those boundary conditions
For every loop, identify your termination/exit conditions
Then test the loop for those exit conditions

64. Your Algorithms & Flowcharts

65. Your Algorithms & Flowcharts
Each of you…

66. Your Algorithms & Flowcharts
Each of you…
Clean sheet of paper(s)

67. Your Algorithms & Flowcharts
Each of you…
Clean sheet of paper(s)
Neatly rewrite your algorithms and flowcharts:

68. Your Algorithms & Flowcharts
Each of you…
Clean sheet of paper(s)
Neatly rewrite your algorithms and flowcharts:
“Largest number” algo

69. Your Algorithms & Flowcharts
Each of you…
Clean sheet of paper(s)
Neatly rewrite your algorithms and flowcharts:
“Largest number” algo
“Smallest number” algo

70. Your Algorithms & Flowcharts
Each of you…
Clean sheet of paper(s)
Neatly rewrite your algorithms and flowcharts:
“Largest number” algo
“Smallest number” algo
“Sort a number list” algo

71. Your Algorithms & Flowcharts
Each of you…
Clean sheet of paper(s)
Neatly rewrite your algorithms and flowcharts:
“Largest number” algo
“Smallest number” algo
“Sort a number list” algo
Separate sheet for each

72. Your Algorithms & Flowcharts
Each of you…
Clean sheet of paper(s)
Neatly rewrite your algorithms and flowcharts:
“Largest number” algo
“Smallest number” algo
“Sort a number list” algo
Separate sheet for each
This will go in your portfolio

73. Clear and Unclear Windows