Quiz 6 Study Guide — Procedures and Functions

Chapter 6: Procedures and Functions

6.1 Procedures

A procedure (Sub procedure) is a named block of code that performs a task and does NOT return a value
Declared with Sub ... End Sub
When called, app branches to the procedure, executes it, then resumes at the next statement after the call
General-purpose procedures are NOT tied to a specific control/event
The Call keyword is optional in VB

6.2 Passing Arguments to Procedures

Arguments — values passed to a procedure/function when called
Parameter — special variable that receives an argument
If a parameter is declared, you MUST supply an argument when calling
Left-to-right assignment: arguments match parameters in order
Pass by value (ByVal) — a COPY is passed; procedure cannot modify original
Pass by reference (ByRef) — procedure has access to original and CAN modify it
ByVal is the default if no keyword is specified

6.3 Functions

A function is a named block of code that performs a task and RETURNS a value
Declared with Function ... End Function
Specify return type: Function Name(args) As DataType
Return a value with the Return statement
Functions can return non-numeric values (String, Boolean, etc.)
Call a function by using it in an expression or assigning to a variable

6.4 Debugging: Step Into, Over, Out

Step Into (F11) — single-step through each line, including called procedures/functions
Step Over (F10) — execute a procedure/function without stepping through its code
Step Out (Shift+F11) — execute remaining statements in current procedure and return to caller
Use Step Over when you trust a procedure and don't need to see its internals
Use Step Out to fast-exit a procedure you accidentally stepped into

Key Concepts

Modularize — dividing an application's code into small, manageable procedures/functions
Local variables are created when procedure starts, destroyed when it ends
Static local variables retain their value between procedure calls
Pascal casing — naming convention where first letter of each word is capitalized
A method is a procedure or function that belongs to an object/class

💡 Key Tip: Know the difference between ByVal vs ByRef, procedure vs function, and the 3 debugging commands (Step Into/Over/Out). These are the most tested concepts!

📝 Practice Quiz — Chapter 6

10 questions. Select your answer, then check the result.

🃏 Flashcards — Chapter 6

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📋 Cheat Sheet — Chapter 6

🔑 Procedure vs Function

PROCEDURE (Sub):         FUNCTION:
Sub Name(args)           Function Name(args) As DataType
    ' code                  ' code
End Sub                    Return value
                         End Function

- Procedure: NO return value
- Function: RETURNS a value via Return

🔑 Passing Arguments

ByVal  → Passes a COPY (default)
ByRef  → Passes a REFERENCE (can modify original)

Sub Calc(ByVal intA As Integer, ByRef intB As Integer)
    intA = 10   ' Only changes local copy
    intB = 20   ' Changes original variable!
End Sub

🔑 Procedure Declaration & Call

' Declaration
Sub DisplayMsg(ByVal strMsg As String)
    MessageBox.Show(strMsg)
End Sub

' Call (Call keyword is optional)
DisplayMsg("Hello")
Call DisplayMsg("Hello")

🔑 Debugging Commands

Step Into  (F11)  → Single-step into called procedures
Step Over  (F10)  → Execute procedure without stepping in
Step Out (F11+F11) → Finish current procedure, return to caller

🔑 Key Vocabulary

Argument     → Value passed when calling
Parameter    → Variable that receives the argument
Static       → Preserves local variable between calls
Modularize   → Break code into small procedures
PascalCase   → Naming: EachWordCapitalized

Tip: Trace through code examples manually — write down what each argument's value is and whether it's ByVal or ByRef.