The `if' Statement
==================

   The `if'-`else' statement is `awk''s decision-making statement.  It
looks like this:

     if (CONDITION) THEN-BODY [else ELSE-BODY]

CONDITION is an expression that controls what the rest of the statement
will do.  If CONDITION is true, THEN-BODY is executed; otherwise,
ELSE-BODY is executed (assuming that the `else' clause is present).
The `else' part of the statement is optional.  The condition is
considered false if its value is zero or the null string, and true
otherwise.

   Here is an example:

     if (x % 2 == 0)
         print "x is even"
     else
         print "x is odd"

   In this example, if the expression `x % 2 == 0' is true (that is,
the value of `x' is divisible by 2), then the first `print' statement
is executed, otherwise the second `print' statement is performed.

   If the `else' appears on the same line as THEN-BODY, and THEN-BODY
is not a compound statement (i.e., not surrounded by curly braces),
then a semicolon must separate THEN-BODY from `else'.  To illustrate
this, let's rewrite the previous example:

     awk '{ if (x % 2 == 0) print "x is even"; else
             print "x is odd" }'

If you forget the `;', `awk' won't be able to parse the statement, and
you will get a syntax error.

   We would not actually write this example this way, because a human
reader might fail to see the `else' if it were not the first thing on
its line.