Ü  DOW (Do While)

·         The RPGLE statements which are to be iterated are placed inside the block created by two opcodes DoW and EndDo.

·         The EndDo represents  the end of DoW block.

·         The RPGLE statements inside these opcodes are iterated till the condition remains true.

·         The looping condition is specified as factor2 of the DoW opcode.

·         The looping condition is checked at the beginning before any iteration begins. If the condition is not true it doesn’t enter the loop even a single time.

Factor 1

Op-code

Factor 2

Result Field

Resulting Indicators

       HI                            LO                      EQ

DOW

Loop expression

 

 

 

 

 

Example


DCount          S              2P 0 Inz
**
C                   DoW       Count < 6
C     Count       Dsply
C                   Eval      Count = Count + 1
C                   EndDo
**
C                   Return

 

             

 

      

OUTPUT

 

DSPLY   0

DSPLY   1

DSPLY   2

DSPLY   3

DSPLY   4

DSPLY   5

 

 

Ü  DOW  Versus  DOU

 

DOW -- Do While -- does the statements in the DO-group while the condition is true. The logical test for the condition happens at the DOW statement, i.e., at the beginning. This implies that the statements won't be executed at all if the condition is false at the time the DOW statement is executed.

 

DOU -- Do Until -- does the statements in the DO-group until the condition is true. The logical test for the condition happens at the ENDDO statement. This implies that the statements will always be executed at least once when the DO-group is reached.

 










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