Conditionals, like IF
decide whether certain
statements need to be executed or not. For instance, suppose you are writing
a tax program. For this, you need to use the EZ form if certain conditions
are met, or the short form if others are met, and the long form otherwise.
You would use a conditional statement to determine which form to use.
There are two types of conditionals: IF/THEN/ELSE
and SELECT CASE
. The IF construct is
useful to check one or more conditions and execute a different block of code
depending on the result. For instance, say that you need to print one
statement if the user is male and under 20, another if the user is male and
between 20 and 40, and still another if the user is male and over 40. The IF
construct works well in this kind of situation.
The SELECT CASE
construct is useful when comparing one main expression with
several values and executing a different block of code for each possible
match. For instance, suppose that in the tax program we mentioned before, you
need to execute a different block of code depending on the user's tax
bracket. SELECT CASE would let you compare a main expression of tax_bracket
all the possible tax brackets (10000-15000, 15000-25000, etc.).
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