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Learning Intention I will learn about evaluating a program.

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Presentation on theme: "Learning Intention I will learn about evaluating a program."— Presentation transcript:

1 Learning Intention I will learn about evaluating a program.

2 Analysis Design Implementation Testing Documentation Evaluation

3 Program Evaluation There are four areas to consider when evaluating a program: Fitness for purpose Efficient use of coding constructs Robustness Readability

4 Fitness for Purpose Software that is fit for purpose - has passed it’s testing (so it’s correct) - meets all the requirements (does what it was supposed to do)

5 Efficiency A program can be written in many different ways and do what it is expected to do Software that is efficient uses the most efficient programming constructs to solve a problem

6 How could this be made more efficient?
DECLARE total INITIALLY 0 RECEIVE number FROM KEYBOARD SET total TO total + number SEND total TO DISPLAY

7 Using repetition (loops) can greatly reduce code
DECLARE total INITIALLY 0 FOR index FROM 1 TO 4 DO RECEIVE number FROM KEYBOARD SET total TO total + number END FOR SEND total TO DISPLAY Using repetition (loops) can greatly reduce code

8 How could this be made more efficient?
DECLARE total INITIALLY 0 RECEIVE number1 FROM KEYBOARD RECEIVE number2 FROM KEYBOARD RECEIVE number3 FROM KEYBOARD RECEIVE number4 FROM KEYBOARD RECEIVE number5 FROM KEYBOARD SET total TO number1 + number2 + number3 + number4 + number5 SEND total TO DISPLAY

9 Using arrays can greatly reduce code
DECLARE number AS REAL INITIALLY [] FOR counter FROM 1 TO 4 DO RECEIVE number(counter) FROM KEYBOARD SET total TO total + number(counter) END FOR SEND total TO DISPLAY Using arrays can greatly reduce code

10 How could this be made more efficient?
IF mark < 50 THEN SET grade TO D END IF IF mark >= 50 AND mark <= 59 THEN SET grade TO C IF mark >= 60 AND mark <= 69 THEN SET grade TO B IF mark >= 70 THEN SET grade TO A Always does all 4 comparisons

11 Does 1, 2 or 3 comparisons depending on the value of mark
IF mark < 50 THEN SET grade TO D ELSE IF mark >= 50 AND mark <= 59 THEN SET grade TO C ELSE IF mark >= 60 AND mark <= 69 THEN SET grade TO B ELSE SET grade TO A END IF Does 1, 2 or 3 comparisons depending on the value of mark

12 Using IF .. ELSE IF … ELSE is more efficient than IF … END IF, IF … END IF

13 Robustness A program is robust if it does not crash, even when it is given invalid input. A robust program will not have any execution errors. A robust program should reject invalid data.

14 Readability Readability means how easy your code is for another programmer to read.

15 Readability – White Space
Using white space means the code is spaced out to make it easier to read.

16 White space

17 Readability - Indentation
Indentation is moving code right a few spaces from the start of the line. (VB does this for you automatically). Using indentation makes it easier to see the code inside different constructs.

18 Readability - Indentation

19 Readability – Meaningful Identifiers
Using meaningful identifiers means using names for objects (TextBoxes, ListBoxes, Buttons etc) and variables which help to describe the information they hold.

20 Readability - Meaningful Identifiers

21 Readability - Meaningful Identifiers

22 Readability – Internal Commentary
Internal commentary is comments you add to your program to help explain what the program is doing. e.g. - why use the variable types you did - why that kind of loop - what the IF statement is trying to decide - etc.

23 Readability – Internal Commentary

24 Complete the Program Evaluation questions.
In your jotter Complete the Program Evaluation questions.

25 I can evaluate a program in terms of:
Success Criteria I can evaluate a program in terms of: Efficiency Readability Robustness Fitness for purpose


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