About learning to program
- 1. ABOUT LEARNING TO PROGRAM ANNA MAKARUDZE PYCON NAMIBIA 2016 TALK 27 JANUARY 2016
- 2. BACKGROUND – MY INTRODUCTION TO PROGRAMMING WHERE • Zimuto High School, Masvingo, Zimbabwe WHEN 1999 – 2002 Ordinary Level (GCE O’ Level), •Subject – Computer Studies •Language – BASIC/DBASE III
- 3. STAGES 1. Define The Task/Tasks 2. Write an Algorithm/ Pseudocode 3. Write Code 4. Debug And Test 5. Deploy
- 4. DEFINE THE TASK/TASKS •The first important task/stage in programming. •Understand what it is you are required to do. •Break down the question/project/task into small tasks. •Can use either bottom/up or top/down modular approach.
- 5. EXAMPLE – DEFINE THE TASKS PROBLEM • Consider a sales rep of a network marketing company selling goods in ZAR but paying in USD. Calculate the USD value of order after discount. Discount rate ranges from 20% to 35% depending on order size. Forex rate uses current rate. The following discount rates apply for a given order size: DISCOUNT RATES Order Size (ZAR) Discount Rate (%) <= 900 20 901-1800 25 1801-2700 30 2701 - 35
- 6. WRITE AN ALGORITHM/PSEUDOCODE •Step by step instructions written in a plain/natural language, e.g. English, Portuguese, etc., which show the actions to be taken in order to achieve a particular goal.
- 7. ALGORITHM/PSEUDOCODE Start Enter the total_value of order in ZAR Enter the current_rate USD:ZAR Determine the discount rate* Calculate total value in USD* Calculate discount* Calculate amount to be paid* Return total value in ZAR, total value in USD, discount and amount to be paid End
- 8. ALGORITHM/PSEUDOCODE – DETAILED DETERMINE DISCOUNT RATE *If total_value <=900 then discount_rate = 20% Else if total_value <= 1800 then discount_rate = 25% Else if total_value <= 2700 then discount_rate = 30% Else discount_rate = 35% End if CALCULATE TOTAL VALUE IN USD AND DISCOUNT RATE *total_value_usd = total_value / current _rate *discount = total_value _usd * discount_rate *amount_due = total_value _usd – discount
- 9. WRITE CODE •Write the program using the syntax of the chosen programming language. •Done in the program’s development environment to enable testing. •In our case, python, using an IDE of your choice.
- 10. IF… STATEMENT - PYTHON if total_value <=900: discount_rate = 0.20 elif total_value <= 1800: discount_rate = 0.25 elif total_value <= 2700: discount_rate = 0.30 else: discount_rate = 0.35
- 11. IF… STATEMENT – C if (total_value <=900) { discount_rate = 0.20; } else if (total_value <= 1800) { discount_rate = 0.25; } else if (total_value <= 2700) { discount_rate = 0.30; } else { discount_rate = 0.35; }
- 12. IF… STATEMENT – C++ if total_value <=900 { discount_rate = 0.20; } else if total_value <= 1800 { discount_rate = 0.25; } else if total_value <= 2700 { discount_rate = 0.30; } else { discount_rate = 0.35; }
- 13. IF… STATEMENT – VISUAL BASIC If total_value <=900 Then discount_rate = 0.20 ElseIf total_value <= 1800 Then discount_rate = 0.25 ElseIf total_value <= 2700 Then discount_rate = 0.30 Else discount_rate = 0.35 End If
- 14. COMPARISON BETWEEN PSEUDOCODE AND CODE ALGORITHM/PSEUDOCODE •Semantics – meaning of your code CODE/PROGRAM •Syntax – gramma of your code
- 15. DEBUG AND TEST •Involves testing the program to determine if it is working as expected. •Process is repeated until the program is running without errors and giving required output. •Normally takes up most of the programmer’s time. •Code normally tends to yield unexpected results.
- 16. DEPLOY •Package your application for deployment and start using your application. •Different languages deploy applications in a different manner. •You therefore need to know how to deploy/publish your app using your IDE.
- 17. RESOURCES USED IN LEARNING PROGRAMMING 2000s • Textbooks • Teacher’s notes and guidance • Projects by students before you 2010 - DATE • Textbooks • Teacher’s notes and guidance • Projects by students before you • Internet - many websites, videos including Stackoverflow, Github, MVA, etc. • PyCons and many other conferences • Learning to program has never been this easy!!!