EVALUATE
















EVALUATE


We can use EVALUATE instead of set of nested IF statements to test 
several conditions. We can use EVALUATE to implement case structure 
or decision table.

Example1 :

EVALUATE WS-INDICATOR
    WHEN “A”
	  DISPLAY “This is Alphabetic filed” 
    WHEN “N”
	 DISPLAY “This is Numeric filed” 
    WHEN “X”
	 DISPLAY “This is Alpha numeric filed” 
    WHEN OTHER
	 DISPLAY “Invalid indicator”
END-EVALUATE


This example evaluates WS-INDICATOR if WS-INDICATOR is ‘A’ displays 
“This is Alphabetic field”, if WS-INDICATOR is ‘N’ displays “This is Numeric 
filed”, if WS-INDICATOR is ‘X’ displays “This is Alpha numeric filed”.  If 
WS-INDICATOR is not ‘A’ or ‘N’ or ‘X’ then it displays “Invalid indicator”.


EVALUATE Exmaple 2 : 

IF operand1 = operand4 AND operand2 = operand5
   Statements block1
ELSE 
   IF operand1 >= operand6 AND operand1 <= operand7 AND operand2 = operand8
   Statements block2
   ELSE 
   Statements block3
   END-IF
END-IF.


We can use following EVALUATE statement instead of above nested IF. 

EVALUTE operand1 ALSO operand2
   WHEN operand4 ALSO opernad5
	Statements block1
   WHEN operand6   THRU   operand7    ALSO    operand8
	Statements block2
   WHEN OTHER
	Statements block3	
END-EVALUATE




Evaluate Example 3:


EVALUATE TRUE ALSO WS-GENDER ALSO WS_AGE

    WHEN WS-INCOME >= 10000 AND < 500000  ALSO  “M”  ALSO  20 THRU 60
          MOVE 13.5 TO WS-RATE 

    WHEN WS-INCOME >= 10000 AND < 500000  ALSO  “F”  ALSO  20 THRU 60  
          MOVE 12.0 TO WS-RATE 
 
    WHEN OTHER
          MOVE 0    TO WS-RATE

END-EVALUATE.


This example is an example of decision table, calculates tax rate based on 
income, age and sex. First WHEN clause will satisfy if condition on income 
(>= 10000 and < 500000) is true, gender is “M” and age is in range of 20 to 
60, if it is true, then MOVE statement after first when will get executed, 
and control come out of EVALUATE.  


If first WHEN condition becomes false, then control goes to second WHEN condi-
tion and check the condition, whether that is true or false, if it is true,
it will execute MOVE statement after the second WHEN condition. if second WHEN
condition is false, then control will go to the MOVE statement coded after WHEN 
OTHER, here it wont check for true or false.