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— Statements —

IF SELECTION

Structured Mode Syntax

IF SELECTION [

NOT
                                UNIQUE

[IN [FIELDS]]] operand1

[THEN] statement

[ELSE statement

]

END-IF

Reporting Mode Syntax

`IF SELECTION` [`NOT UNIQUE` [`IN` [`FIELDS`]]] `operand1`
	[`THEN`]	`statement`
		`DO` `statement` `DOEND`
	`ELSE`	`statement`
		`DO` `statement` `DOEND`

This document covers the following topics:

Function
Syntax Description
Example

For an explanation of the symbols used in the syntax diagram, see Syntax Symbols.

Related Statements: DECIDE FOR | DECIDE ON | IF

Belongs to Function Group: Processing of Logical Conditions

Function

The IF SELECTION statement is used to verify that in a sequence of alphanumeric fields one and only one contains a value.

Syntax Description

Operand Definition Table:

Operand	Possible Structure					Possible Formats													Referencing Permitted	Dynamic Definition
`operand1`		S	A			A	U								L	C			yes	no

Syntax Element Description:

Syntax Element	Description
`operand1`	Selection Field(s): As `operand1` you specify the fields which are to be checked. If you specify an attribute control variable (Format C), it is considered to contain a value if its status has been changed to `MODIFIED`. Note: To check if a specific attribute control variable has been assigned the status `MODIFIED`, use the `MODIFIED` option of, for example, an `IF` statement. This enables you to check that exactly one field was modified.
`THEN statement ...`	THEN Clause: The statement(s) specified in the `THEN` clause will be executed if one of the following conditions is true: None of the fields specified in `operand1` contains a value. More than one of the fields specified in `operand1` contains a value. This statement is generally used to verify that a terminal user has entered only one function in response to a map displayed via an `INPUT` statement. Note: If no action is to be performed if one of the conditions is met, you specify the statement `IGNORE` in the `THEN` clause.
`ELSE` `statement ...`	ELSE Clause: In the `ELSE` clause, you specify the statement(s) to be executed if exactly one field contains a value.
`END-IF`	End of IF SELECTION Statement: In structured mode, the Natural reserved word `END-IF` must be used to end the `IF SELECTION` statement. In reporting mode, use the `DO ... DOEND` statements to supply one or several suitable statements, depending on the situation, and to end the clauses and the `IF SELECTION` statement. If you specify only a single statement, you can omit the `DO ... DOEND` statements. With respect to good coding practice, this is not recommended.
`statement ...` `DO statement ... DOEND`

Example

** Example 'IFSEL': IF SELECTION                                        
************************************************************************
DEFINE DATA LOCAL                                                       
1 #A (A1)                                                               
1 #B (A1)                                                               
END-DEFINE                                                              
*                                          
INPUT 'Select one function:' //            
   9X 'Function A:' #A                     
   9X 'Function B:' #B                     
*                                          
IF SELECTION NOT UNIQUE #A #B              
  REINPUT 'Please enter one function only.'
END-IF                                    
*                                          
IF #A NE ' '                               
  WRITE 'Function A selected.'             
END-IF                                     
IF #B NE ' '                               
  WRITE 'Function B selected.'             
END-IF                                     
*                                          
END

Output of Program IFSEL:

Select one function:                        
                                            
         Function A:           Function B:

After selecting and confirming function A:

Page      1                                                  05-01-17  11:04:07
                                                                               
Function A selected.

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