Fundamentals Topic 1 Programming basics

1. Objectives

  • Define the following key concepts:

    • Algorithm

    • Pseudocode

  • Understand data types and their uses.

  • Familiarize with basic arithmetic operations in programming.

  • Learn about string handling operations.

  • Distinguish between variables and constants.

  • Write pseudocode for simple problems.

2. Algorithms

  • Definition: An algorithm is a sequence of instructions to solve a problem.

  • Example Problem: Calculate the amount of paint needed to paint a room.

  • Questions to Consider:

    • What inputs are needed?

    • What decisions does the painter have to make?

    • Steps to take:

      • Input the dimensions of the room.

      • Use programming statements like Input, Calculate, Output, and arithmetic symbols ( +, -, * ).

3. Pseudocode

  • Definition: A method to write instructions using natural language and programming elements.

  • Purpose: Helps in planning code before implementation.

    • Provides a structure to think through the steps needed.

    • Streamlines the coding process.

  • Structure: Typically, pseudocode uses a blend of English-like syntax combined with programming syntax.

3.1. Pseudocode Statements

  • Assignment Example:

    • currentMileage = previousMileage + 1

  • Input/Output Examples:

    • OUTPUT "Enter current mileage"

    • currentMileage = USERINPUT

3.2. Comparison with Visual Basic

  • Pseudocode Example:

    • OUTPUT "Enter a number"

    • number = USERINPUT

    • IF number > 4 THEN OUTPUT "Greater than 4" ELSE OUTPUT "4 or less" ENDIF

  • Visual Basic Example:

    • Dim number As Integer = 0

    • Console.Write("Enter a number")

    • number = Console.ReadLine()

    • If number > 4 Then Output "Greater than 4" Else Output "4 or less" End If

4. Variables and Assignment

  • Identifier: A name that points to a memory location (e.g., Score).

  • Assignment: Assigning values to variables.

  • Example:

    • Dim Score As Integer = 0

    • Score = Score + 1

5. Data Types

  • Variable Declarations in Visual Basic:

    • Dim wholeNumber As Integer = 5

    • Dim height As Decimal = 1.5

    • Dim name As String = "Bob"

    • Dim choice As Char = "a"

    • Dim validData As Boolean = False

  • Python Behavior: Variables don’t need explicit type declaration when data is assigned.

5.1. Data Type Operations

  • Character Assignment to Integer: Assigning a character like "9" to an integer variable may cause type mismatch issues.

  • Boolean Values: Acceptable values are either True or False.

6. Variables and Constants

  • Variable Characteristics:

    • Values can be modified during execution.

  • Constant Characteristics:

    • Value cannot be changed once defined.

    • Example Code:**

    • Const VAT As Single = 17.5

6.1. Benefits of Constants

  • Reduces the risk of errors by limiting access to memory locations.

  • Example: Would you declare 3.14159265359 as a variable or a constant? (It should be a constant.)

7. Operators

  • Mod and Div Operators:

    • Mod Operator: Returns the remainder of an integer division.

    • Div Operator: Returns the integer part of the division.

  • Example Calculations:

    • 17 mod 3 yields 2

    • 17 div 3 yields 5

8. String Handling Functions

  • Programming languages offer built-in string functions.

  • Examples:

    • name = "Robert"

    • x = len(name) (returns length of string)

    • Checks presence of substring using find() method:

      • x = name.find("be") (returns index position or 0 if not found)

8.1. Practical Application

  • Evaluating return values for string functions for example strings:

    • Consider name = "John"

    • Outputs of x = len(name) and x = name.find("be") are evaluated.

9. Worksheet Activities

  • Complete the Worksheet tasks as assigned in units. The tasks provide practical application of the programming concepts discussed.