Natural for OpenVMS Version 6.3.12 for OpenVMS
 —  Statements  —

REPEAT

This document covers the following topics:

Related Statements: FOR | ESCAPE

Belongs to Function Group: Loop Execution


Function

The REPEAT statement is used to initiate a processing loop.

See also Loop Processing in the Programming Guide.

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Syntax Description

Two different structures are possible for this statement.

The placement of the logical condition (either at the beginning or at the end of the loop) determines when it is to be evaluated.

For further information on logical conditions, see the section Logical Condition Criteria in the Programming Guide.

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

Syntax 1:

REPEAT            
   statement

UNTIL

logical-condition

WHILE
END-REPEAT (structured mode only)
LOOP (reporting mode only)

Syntax 2:

REPEAT  
 

UNTIL

logical-condition

statement
WHILE
 
END-REPEAT (structured mode only)  
LOOP (reporting mode only)  

Syntax Element Description:

Syntax Element Description
UNTIL
UNTIL Option:

The processing loop will be continued until the logical condition becomes true.

WHILE
WHILE Option:

The processing loop will be continued as long as the logical condition is true.

logical-condition
Logical Condition:

If a logical condition is specified, the condition determines when the execution of the loop is to be terminated.

If no logical condition is specified, the loop must be exited by an ESCAPE, STOP or TERMINATE statement specified within the loop.

The syntax for a logical condition is described in the section Logical Condition Criteria in the Programming Guide.

END-REPEAT
End of REPEAT Statement:

In structured mode, the Natural reserved word END-REPEAT must be used to end the REPEAT statement.

In reporting mode, the Natural statement LOOP is used to end the REPEAT statement.

LOOP

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Examples

Example 1 - REPEAT

** Example 'RPTEX1S': REPEAT (structured mode)                          
************************************************************************
DEFINE DATA LOCAL                                                       
1 EMPLOY-VIEW VIEW OF EMPLOYEES                                         
  2 PERSONNEL-ID                                                        
  2 NAME                                                                
*                                                                       
1 #PERS-NR (A8)                                                         
END-DEFINE                                                              
*                                                                       
REPEAT                                                            
  INPUT 'ENTER A PERSONNEL NUMBER:' #PERS-NR                            
  IF #PERS-NR = ' '                                                     
    ESCAPE BOTTOM                                                       
  END-IF                                                                
  /*                                                                    
  FIND EMPLOY-VIEW WITH PERSONNEL-ID = #PERS-NR                         
    IF NO RECORD FOUND                                                  
      REINPUT 'NO RECORD FOUND'                                         
    END-NOREC           
    DISPLAY NOTITLE NAME
  END-FIND              
END-REPEAT          
*                       
END                    

Output of Program RPTEX1S:

ENTER A PERSONNEL NUMBER: 11500304

After entering and confirming personnel number:

        NAME        
--------------------
                    
KLUGE              

Equivalent reporting-mode example: RPTEX1R.

Example 2 - Using WHILE and UNTIL Options

** Example 'RPTEX2S': REPEAT (with WHILE and UNTIL option)              
************************************************************************
DEFINE DATA LOCAL                                                       
1 #X (I1) INIT <0>                                                      
1 #Y (I1) INIT <0>                                                      
END-DEFINE                                                              
*                                                                       
REPEAT WHILE #X <= 5                                              
  ADD 1 TO #X                                                           
  WRITE NOTITLE '=' #X                                                  
END-REPEAT                                                           
*                                                                       
SKIP 3                                                                  
REPEAT                                                             
  ADD 1 TO #Y                                                           
  WRITE '=' #Y
  UNTIL #Y = 6                                                          
END-REPEAT                                                             
*                                                                       
END

Output of Program RPTEX2S:

#X:    1 
#X:    2 
#X:    3 
#X:    4 
#X:    5 
#X:    6 
         
         
         
#Y:    1 
#Y:    2 
#Y:    3 
#Y:    4 
#Y:    5 
#Y:    6

Equivalent reporting-mode example: RPTEX2R.

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