Using nested IF statements
If an IF statement contains an IF statement
as one of its possible branches, the IF statements
are said to be nested. Theoretically, there is no limit
to the depth of nested IF statements.
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However, use nested IF statements sparingly.
The logic can be difficult to follow, although explicit scope terminators
and indentation can help. If a program has to test a variable for
more than two values, EVALUATE is probably a better
choice.
The following pseudocode depicts a nested IF statement:
IF condition-p
IF condition-q
statement-1
ELSE
statement-2
END-IF
statement-3
ELSE
statement-4
END-IF
In the pseudocode above, an IF statement
and a sequential structure are nested in one branch of the outer IF.
In this structure, the END-IF that closes the nested IF is
very important. Use END-IF instead of a period, because
a period would end the outer IF structure also.
The following figure shows the logic structure of the pseudocode above.
