1. Introduction to Algorithm Design and Documentation CSIS 1595: Fundamentals of Programming and Problem Solving 1

2. Stages of Program Development Analysis: What must the program do? Design: How should the program work? Implementation: Coding the program Testing: Making sure the program works Maintenance: Upgrading to meet new requirements

3. Example Requirements: Write program to compute taxes. Taxes are computed as the tax rate (currently 20%) times taxable income. Taxable income is gross income minus total deductions. Total deductions are a standard deduction (currently $10,000) plus a dependent deduction (currently $3,000) times the number of dependents. Implementation: Very difficult to do this directly

4. Algorithms and Pseudocode Algorithm: Set of steps to solve problem – Usually pseudocode – Can use to implement code Example: Computing Celsius temperature 1.Ask user for Fahrenheit temperature 2.Compute Celsius temperature from the Fahrenheit temperature 3.Display the Celsius temperature to the user

5. Algorithm Design Often involves refining for more detail – Additional steps – Detail about computation Example: Computing Celsius temperature 1.Ask user for Fahrenheit temperature 1.Convert to floating point value 2.Compute Celsius temperature from Fahrenheit temperature using formula (Fahrehneit – 32)/1.8 3.Display the Celsius temperature to the user

6. Readability Code must be easily understood by people – Other programmers who maintain your code – Yourself in future Descriptive variable names White space – Spaces between words on same line – Blank lines between sections of code Comments (documentation)

7. Comments Comments: Text in program meant to explain how it works – What each section does – How it does it (if not obvious) – Often includes header that briefly describes what program does as a whole Syntax in Python: # comment – Anything after the # is ignored by the Python interpreter

8. Comments Can create directly from pseudocode – Often write comments before writing code