# Conditional Functions

## If Statements

Syntax

Any of the following forms may be used:

 Example 1 Single Condition and Single Outcome Example 2 Single Condition, outcome when true or False Example 3 Multiple conditions, multiple outcomes if ( expression1 ) statements1 endif if ( expression1 ) statements1 else statements2 endif See also: IIf function if ( expression1 ) statements1 elseif ( expression2 ) statements2 elseif ( expression3 ) statements3 etc... else statementsN endif

All expressions must resolve into a single Boolean (true or false) result.

statements1 : are executed if expression1 is True, otherwise they are ignored.
statements2 : are executed if expression1 is False and expression2 is True, otherwise they are ignored.
statements3 : are executed if both expression1 and expression2 are False and expression3 is True, otherwise they are ignored.
statementsN : is executed if all preceding expressions are false.

• ElseIf and hence the associated expression2 and statements2 etc - are optional.
• numerous ElseIfs are allowed, before the Else/EndIf.
• else and hence the associated statementsN - are optional.
• If, EndIf keywords (and their associated ElseIf, Else keywords ) can be nested (included within other If-EndIf statements.

Examples

Example 1:

```if (FeedFlow > 0.01)
Recovery = Product/FeedFlow
endif
```

Example 2:

```if (FeedFlow == 0)
Recovery = 0
else
Recovery = Product / FeedFlow
endif
```

Example 3:

```if (UnitTemperature > 100)
Reaction_Extent = 98
elseif (UnitTemperature  > 80)
Reaction_Extent = 82
elseif (UnitTemperature  >= 30)
Reaction_Extent = 75
else
Reaction_Extent = 43
endif
```

## IIf

Syntax

variable = IIf(expression, truePart , falsePart)

expression : must eventually resolve into a single boolean (true or false) result.
truePart : Value or expression.
falsePart : Value or expression.

The IIf function, returns one of two parts depending on the evaluation of an expression. The expression is evaluated, if the expression result is true then truePart is evaluated and returned as the result of the IIf function. If the expression result is false then falsePart is evaluated and returned as the result of the IIf function. Note that only one of the two parts is evaluated.

Examples

Example 1:

```Recovery = iif(FeedFlow==0, 0, Product/FeedFlow)
;This is equivalent to the following statements using 'if' and 'else':
;if (FeedFlow==0)
;  Recovery  = 0
;else
;  Recovery  = Product/FeedFlow
;endif
```

Example 2:

```ReactionExtent = iif(AutoclaveTemperature >=190, 98, 50)
;This is equivalent to the following statements using 'if' and 'else':
;if (AutoclaveTemperature >=190)
;  ReactionExtent = 98
;else
;  ReactionExtent = 50
;endif
```

## While Statements

Syntax

```While (expression)
Statements
EndWhile
```

expression : must eventually resolve into a single boolean (true or false) result.
statements : will repeatedly be executed while the expression is true (non zero).

If the expression is false, the statements will be ignored.

• A While ... EndWhile block is an excellent way of implementing a loop.
• While instructions can be nested.
• There is no limit to the number of statements inside the While ... EndWhile block.

Examples

``` Integer LoopCount*

LoopCount = 5
while (LoopCount>0)
; *** do loop logic here ***
LoopCount = LoopCount - 1
; *** or do loop logic here ***
EndWhile
```