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A Guide to Working with Visual Logic - Vocabulary Flashcards

Visual Logic Notes

Introduction to Input, Process, Output

  • A computer program is a solution to a problem.
  • Most useful programs do at least 3 things: input data, process data, output resulting information.
  • Visual Logic emphasizes the Input → Process → Output flow, often shown explicitly as INPUT PROCESS OUTPUT.

Real-world example: Internet Shopping Cart System

  • Data items involved:
    • Customer ID
    • Mailing address
    • Credit card number
    • Product
  • Procedures the system performs:
    • Connect to Database
    • Determine product cost
    • Calculate sales tax
    • Bill customer
    • Print customer receipt
    • Generate shipping label
    • Generate report for sales department
  • Emphasizes the same IO structure: INPUT → PROCESS → OUTPUT.

Algorithms, Flowcharts, and Pseudocode

  • An algorithm is the blueprint for a computer program/software.
  • Tools for representing algorithms include:
    • Flowcharts
    • Pseudocode
  • Visual Logic is a visual tool that combines graphics of flowcharts with pseudocode-like syntax.
  • Visual Logic can animate or execute the algorithm.
  • Important distinction: Visual Logic is NOT a computer programming language.
  • After an algorithm is developed, it must be coded in a programming language to be run on a computer.

Simple Programming Formats: Variables, Input, Output

  • An output statement displays information (in a window/console/file).
  • An input statement accepts data from the user and stores that data into a variable.
  • A variable is a storage location in computer memory that can be accessed and changed in the program.

Variables and Identifiers

  • A variable has a name (identifier) and an associated data value (which may change during execution).
  • Example: NAME is a variable; its data value could be the string "Dave".
  • The name of a variable is called an identifier.
  • Legal identifiers:
    • NAME
    • num1
    • interestRate
    • Num_1
    • Num_2
  • An identifier cannot have spaces; allowed characters are letters, numbers and underscore (_).
  • Visual Logic is case-insensitive.

Hello Name Program: Strings vs Outputs

  • When inputting a string, the value MUST be entered inside quotes (" ").
  • However, when displaying the output string, quotes are not shown.

Input Statement Summary (Visual Logic)

  • Input statements are used to get data into variables.
  • In Visual Logic, the input flowchart element is a parallelogram with the keyword Input followed by the variable name (e.g., Input: NAME).
  • When the input statement is executed:
    • The user is prompted to enter a value using the keyboard.
    • The typed value is stored in the variable for later use.
  • String input rules: place string values inside quotes.
  • Numeric input rules:
    • Contain only digits and possibly one decimal point.
    • Percent symbols (%), dollar signs ($), commas (,), or any other symbols are not allowed.

Partial Weekly Paycheck Solution (Illustrative Flow)

  • Flow components include:
    • Begin
    • Input: Hours
    • Input Dialog: "Please type a value for HOURS:"
    • [User enters] 40
    • Input: Rate
    • [Input Dialog] "Please type a value for RATE:"
    • [User confirmation] (check/OK selected)
    • Pay = Hours * Rate
    • [Result display] 50.75
    • End
  • This example demonstrates the calculation and the display of a computed result.

Assignment Statements

  • Assignment statements perform calculations and store the result.
  • A key processing step; its flowchart shape is a rectangle.
  • Structure:
    • LHS: a variable on the left-hand side.
    • RHS: an expression on the right-hand side.
    • An equal sign (=) sits in the middle.
  • When executed, the RHS expression is evaluated first, and that value is stored in the LHS variable.
  • Variables hold values and have names; they are memory locations.

Weekly Paycheck: Partial Solution (Garbled Note)

  • Pay will have the value: ??2030 Do you see the t t?
  • This appears to be a fragment or transcription artifact from the example run.

Weekly Paycheck: No Formatting (Flow Outline)

  • Flow structure:
    • Begin
    • Input: Hours
    • Input Dialog: "Please type a value for HOURS:"
    • OK
    • Input: Rate
    • Input Dialog: "Please type a value for RATE:"
    • OK
    • Pay = Hours * Rate
    • Output: Pay
    • End
  • Example values shown in this transcript:
    • Hours entry: 40
    • Rate entry: 12
    • Pay computation: Hours × Rate
    • Result shown: 50.75
    • Additional lines shown: 2030, X (these appear as part of the transcript’s sample output window rather than a fixed result)

Weekly Paycheck: Complete Solution and Currency Formatting

  • FormatCurrency is an intrinsic function that formats the variable inside the parentheses with:
    • a leading dollar sign ($)
    • a decimal point
    • two places after the decimal point
  • Important note: The shape of the Output shape in Visual Logic is different from Input in Visual Logic.
  • Example idea: If Pay = 50.75, then FormatCurrency(Pay) would display as $50.75.

Weekly Paycheck: No Formatting versus Formatting

  • Question raised: What would you see if you used FormatCurrency? (No explicit screenshot, but the implication is that without formatting, Pay might display as a plain number, e.g., 50.75, whereas with formatting you see a currency string like $50.75.)

Weekly Paycheck: Formatting Details

  • FormatCurrency – rounds off to 2 decimal places.
  • The transcript emphasizes two key points about formatting:
    • Formatting converts numeric values into a currency string with two decimal places.
    • Without formatting, the numeric value may be shown without a dollar sign or decimal precision enhancements; with formatting, it appears as currency.

Key Takeaways and Concepts to Remember

  • IO model: input → process → output is fundamental to programming and problem solving.
  • Visual Logic provides a visual method to design algorithms using flowcharts and pseudocode-like syntax, but it is not itself a programming language.
  • Variables and identifiers:
    • Names must be valid identifiers (no spaces; letters, numbers, underscores allowed).
    • Visual Logic is case-insensitive, reducing some naming errors.
  • Input statements:
    • Use a parallelogram with the keyword Input.
    • Strings must be quoted; numeric input must be digits with optional one decimal point; avoid punctuation and symbols.
  • Output statements:
    • Display information; the formatting can affect how values appear (e.g., currency formatting).
    • FormatCurrency is an intrinsic function to display monetary values with $ and two decimals.
  • Assignment statements:
    • Rectangle shape in the flowchart.
    • Math expressions evaluate on the right-hand side first, then stored in the left-hand side variable.
  • Real-world relevance:
    • Banking/Payroll examples illustrate calculations and formatting in workplace contexts.
    • A shopping cart workflow shows how IO, processing, and reporting interact in business systems.
  • Practical implications:
    • Handling of sensitive data (e.g., credit card numbers) requires attention to privacy and security beyond the basic Visual Logic example.
  • Connections to broader concepts:
    • The material complements foundational programming topics such as problem decomposition, algorithm design, and transitioning from visual representations to actual code.

Quick Formula Recap (LaTeX)

  • Pay calculation in a typical payroll example:
    • ext{Pay} = ext{Hours} imes ext{Rate}
  • Currency formatting example:
    • $$ ext{FormatCurrency}( ext{Pay}) = ext{\