Data Types
----------

   The value of an `awk' expression is always either a number or a
string.

   Certain contexts (such as arithmetic operators) require numeric
values.  They convert strings to numbers by interpreting the text of
the string as a numeral.  If the string does not look like a numeral,
it converts to 0.

   Certain contexts (such as concatenation) require string values.
They convert numbers to strings by effectively printing them with
`sprintf'.  See Conversion of Strings and Numbers: Conversion, for
the details.

   To force conversion of a string value to a number, simply add 0 to
it.  If the value you start with is already a number, this does not
change it.

   To force conversion of a numeric value to a string, concatenate it
with the null string.

   The `awk' language defines comparisons as being done numerically if
both operands are numeric, or if one is numeric and the other is a
numeric string.  Otherwise one or both operands are converted to
strings and a string comparison is performed.

   Uninitialized variables have the string value `""' (the null, or
empty, string).  In contexts where a number is required, this is
equivalent to 0.

   See Variables, for more information on variable naming and
initialization; see Conversion of Strings and Numbers: Conversion.,
for more information on how variable values are interpreted.