2.0 Subs, Functions, Decisions, Flowcharts

Question 1

modular programming

Answer 1

info needs to be broken down into parts and organized
-computer programs are organized in modules
▪ independent and self-contained
▪ designed for specific well-defined function
▪ focused and short
- a module can have one or more procedures
▪ each procedure small and self-contained
▪ eg. subs and functions

Question 2

sub procedures

Answer 2

take more than one input parameter
- returns more than one result
- cannot be used in an expression
- general syntax:
Sub name([arglist])
[statements]
[Exit Sub]
[statements]
End Sub

• the argument list of the first (main) Sub to be executed is BLANK
• the arglist Subs that are called by other Subs usually has one or more arguments
• a Sub can call another Sub to perform a part of the task
  ▪ after Call statement executed, the statements in name2 are executed, then execution resumes in
  name1 right before the Call name2 statement

Question 3

functions

Answer 3

can take more than one input parameter
- returns only ONE RESULT
- can be used in formula to return the result in a cell or in an expression in a Sub
- general syntax:
Function name([arglist]) [statements]
[name = expression] [Exit Function] [statements]
[name = expression]
End Function

Question 4

structured programming

Answer 4

program statements are executed sequentially
▪ line by line
▪ starting at top and moving down to end
▪ creates limitations and inconveniences
- conventions to impose order on non-sequential algorithms that have been developed
- to allow program to take nonconsequential paths, ALL computer languages include statements
▪ decisions = branching of flow based on decision * 3 basic types
- If/Then/Else structures
- If/Then/Else If Cascade structures
- Select Case structures
▪ loops = looping of flow to allow statements to be repeated

Question 5

how to tackle a problem while writing a code?

Answer 5

▪ think about the problem you’re trying to solve
▪ outline several possible methods of solutions
▪ select method that seems most clear and concise
▪ construct a detailed step-by-step procedure = an algorithm

Question 6

flowcharts

Answer 6

for complicated algorithms, where decisions and/or looping occur, it’s more convenient to represent the algorithm with a flowchart
-graphical representation of an algorithm
-helps visualize the flow of the solution process
-must draw a flowchart before starting to write a code
-a series of blocks and arrows
- each block represents particular operation
- arrows represent sequence of those operations
(see photo)

Question 7

If/Then/Else decision structure

Answer 7

syntax:
If condition Then [TrueStatements]
Else
[FalseStatements]
End If
- condition is a logical expression that evaluates
“TRUE” or “FALSE”
- true statements are one or more statements that are
executed if condition is TRUE
- false statements are one or more statements that are
executed if condition is FALSE
(See Photo)

Question 8

If/Then block structure

Answer 8

-True statements are one or more statements that are executed if condition is True
-False statements goes straight to junction

Question 9

loops

Answer 9

when you want to execute a statement or group of statements many times, use Do/Loop structure

Question 10

“Do/If Exit” and “For/Next”

Answer 10

count-controlled loops
-using “Do/If Exit” to loop pre-specified number of times
-For/Next loop provides a much more efficient means of implementing count-controlled iteration

Question 11

Nesting

Answer 11

loops that are enclosed completely with other loops

Question 12

Orders of Priority in Evaluating Operators

Answer 12

Arithmetic: Parenthesis, Exponents, negation, multiplication/division, addition/subtraction
Relational: =, <>, <,>,<=,>=
Logical: Not, And, Or

Question 13

Relational Operators

Answer 13

= Equals or is equal to
<> Is not equal to
< Is less than
> Is greater than
<= Is less than or equal to
>= Is greater than or equal to

Question 14

algorithm

Answer 14

a set of instructions which, when followed, will produce a solution to the problem

Question 15

select case structure

Answer 15

• takes the “If/Then/Else If” to its logical conclusion
• Select Case TextExpression [Case expression list1
  [statements]] [Case expression list2
  [statements]] [Case Else
  [elsestatements]]
  End Select
  -e.g. grade

Question 16

Do/If Exit

Answer 16

decision terminates if a condition is true
- general syntax:
Do
[statements]
If Condition Then Exit Do
[statements] Loop
- condition is a logical condition that tests “TRUE” or “FALSE”
- a single line “If” statement is used to exit the loop if condition is “TRUE”
- “FALSE” statements are one or more statements executed if the condition is “FALSE”