Introduction to Computing and Problem Solving

Every computer program follows the same basic pattern: Input → Process → Output. Programs take data from sources like keyboards or files, manipulate it according to instructions, and produce results on screens or in files.

Visual Basic uses zero-based numbering, meaning counting starts at 0 instead of 1—an important concept to remember when programming. When developing a program (also called an application, project, or solution), you'll follow the Program Development Cycle.

💡 Remember that computers only do exactly what they're told! If your program doesn't work correctly, it's because the instructions need refinement, not because the computer misunderstood.

The key to successful programming is breaking down complex problems into smaller, manageable tasks that can be expressed in programming language. Your job as a programmer is to create these clear instructions.

Program Development Cycle

Creating a successful program means following a structured approach. The Program Development Cycle has six essential steps:

1. Analyze: Define the problem clearly, identifying what you need to accomplish
2. Design: Plan your solution by determining output, identifying required input, and mapping the process
3. Choose the Interface: Select appropriate objects like text boxes and buttons
4. Code: Translate your algorithm into programming language
5. Test and debug: Find and fix errors in your program
6. Document: Organize all materials that describe the program

Good programmers don't jump straight to coding. Instead, they use planning tools like flowcharts, pseudocode, and hierarchy charts to visualize solutions before writing any code.

When planning your algorithm, always work backward: first determine the desired output, then identify what input you need, and finally figure out the steps to transform that input into output.

Programming Tools

Flowcharts use standardized symbols to visually map program logic. Each symbol has a specific meaning:

• Flowlines (arrows) connect symbols and show logic flow
• Terminals (rounded rectangles) mark start/end points
• Input/Output symbols (trapezoids) represent data being read or displayed
• Processing symbols (rectangles) show calculations or data manipulation
• Decision symbols (diamonds) represent yes/no choices with two exit paths
• Connectors (circles) join flowlines

Hierarchy charts $also called structure charts or top-down charts$ show how different parts of a program relate to each other, creating a visual roadmap of program organization.

🔑 The beauty of planning tools like flowcharts and pseudocode is that they're language-independent—you can use them to plan your solution regardless of what programming language you'll ultimately use.

These visual tools help you think through your solution before writing a single line of code, making the actual coding process much smoother.

Using Planning Tools

When working with a flowchart, you trace it by starting at the beginning symbol and following the flow lines to the end, just as a computer would execute your program.

Let's look at a sample flowchart for a postage-stamp program:

1. Start by obtaining the number of sheets
2. Calculate stamps needed by dividing sheets by 5
3. Round up to the nearest whole number if necessary
4. Display the number of stamps needed

Flowcharts, pseudocode, and hierarchy charts are language-independent tools—they help you plan your logic regardless of what programming language you'll use to implement the solution.

These planning tools might seem like extra work at first, but they save tremendous time later by helping you catch logical errors before you start coding. The clearer your plan, the smoother your coding process will be.

Introduction to Visual Basic

Visual Basic is a powerful language for creating Windows applications with a Graphical User Interface (GUI). What makes Visual Basic special is that it's event-driven—the program responds to user actions like clicking buttons or typing text.

Developing a Visual Basic program follows three main steps:

1. Design the user interface with controls
2. Determine which events the controls should recognize
3. Write event procedures to handle those events

Visual Basic offers several important controls for building interfaces:

• Text box controls for input and output
• Button controls that users click to trigger actions
• Label controls to identify other interface elements
• List box controls to display multiple items

💡 Think of your program interface as a conversation with the user. Each control is a way for users to communicate with your program or for your program to communicate back.

The interface design is crucial—a well-designed interface makes your program intuitive and easy to use, regardless of how complex the underlying code might be.

Visual Basic Screen and Controls

The Visual Basic development environment contains several key parts:

• Form Designer where you visually create your interface
• Toolbox containing controls you can add to your form
• Properties window for customizing controls
• Solution Explorer to manage project files

You can place controls on your form in four different ways:

1. Double-clicking the control in the toolbox
2. Dragging and dropping from the toolbox
3. Clicking the control and then clicking on the form
4. Clicking the control and then dragging on the form

Text Box controls are versatile elements used for both input and output. When using text boxes for output only, set the ReadOnly property to True to prevent users from changing the displayed information.

Controls can be adjusted using the sizing handles that appear when you select them. These small squares let you resize controls precisely to fit your interface design needs.

Working with Control Properties

Every control in Visual Basic has properties that determine its appearance and behavior. The Properties window displays all available properties for the currently selected control.

For text boxes, important properties include:

• ReadOnly: Determines if users can modify the content
• ScrollBars: Adds scrolling capability for large text
• TabIndex: Sets the order controls are selected when pressing Tab
• Text: The content displayed in the text box
• TextAlign: Controls how text is aligned (left, center, right)

The Properties window is divided into two columns—the left shows property names, and the right displays their current values. The description pane at the bottom provides helpful information about the selected property.

When a control is selected, sizing handles appear around it, allowing you to resize it by dragging. The Tasks button provides quick access to common operations for the selected control.

Setting Control Properties

Every control has properties that determine how it looks and behaves. Some of the most commonly adjusted properties include:

• Text: The text displayed on or in the control
• AutoSize: Whether the control automatically resizes to fit its content
• Font.Name and Font.Size: The typeface and size of text
• ForeColor: The color of text
• BackColor: The background color of the control
• ReadOnly: For text boxes, prevents user editing

To change a property:

1. Select the control
2. Find the property in the Properties window
3. Enter a new value or select from available options

🔧 Mastering the Properties window is crucial for efficient development. Learning keyboard shortcuts for common property adjustments can significantly speed up your workflow.

The Font property requires special handling—click on the ellipsis (...) button to open the Font dialog where you can select the font family, style, and size all at once.

More Essential Controls

Button controls are the workhorses of Visual Basic applications. The button's Text property sets its caption, which should clearly indicate what happens when clicked. For example, a button that calculates totals might be labeled "Calculate" or "Compute Total."

Label controls help users understand your interface by identifying what other controls are for. Some important label properties:

• The Text property sets what the label displays
• By default, the AutoSize property is True, making labels resize automatically
• Setting AutoSize to False lets you manually resize labels for multi-line text

The Font dialog gives you complete control over text appearance:

• Select font families from the left list
• Choose styles (Regular, Bold, Italic) from the middle list
• Set the size from the right list
• Preview your selections in the sample box

After making your font selections, click OK to apply them to your control. A well-chosen font enhances both readability and the professional appearance of your application.

Advanced Controls and Naming Conventions

List Box controls display multiple items, making them perfect for showing several results at once. Users can select items from the list, making it interactive.

The Name property is crucial for programming—it's how you'll refer to controls in your code:

• Always use the three-character prefix convention (btn, lbl, txt, lst)
• Follow the prefix with a descriptive name (btnCompute, txtAddress)
• Good naming makes your code more readable and maintainable

When designing your interface, consider font choices carefully:

• Proportional fonts like Microsoft Sans Serif use different widths for different characters
• Fixed-width fonts like Courier New use the same width for every character
• Use fixed-width fonts when creating tables or when alignment matters

💡 The Auto Hide feature helps manage screen space by automatically collapsing windows like the Toolbox when not in use. Look for the push pin icon—horizontal means Auto Hide is enabled, vertical means it's disabled.

Remember that a well-designed interface with consistent naming conventions makes your program easier to use and your code easier to maintain.