(gawk) Conditional Exp

 
 Conditional Expressions
 =======================
 
    A "conditional expression" is a special kind of expression with
 three operands.  It allows you to use one expression's value to select
 one of two other expressions.
 
    The conditional expression is the same as in the C language:
 
      SELECTOR ? IF-TRUE-EXP : IF-FALSE-EXP
 
 There are three subexpressions.  The first, SELECTOR, is always
 computed first.  If it is "true" (not zero and not null) then
 IF-TRUE-EXP is computed next and its value becomes the value of the
 whole expression.  Otherwise, IF-FALSE-EXP is computed next and its
 value becomes the value of the whole expression.
 
    For example, this expression produces the absolute value of `x':
 
      x > 0 ? x : -x
 
    Each time the conditional expression is computed, exactly one of
 IF-TRUE-EXP and IF-FALSE-EXP is used; the other is ignored.  This is
 important when the expressions have side effects.  For example, this
 conditional expression examines element `i' of either array `a' or
 array `b', and increments `i'.
 
      x == y ? a[i++] : b[i++]
 
 This is guaranteed to increment `i' exactly once, because each time
 only one of the two increment expressions is executed, and the other is
 not.   Arrays in `awk' Arrays, for more information about arrays.
 
    As a minor `gawk' extension, you can continue a statement that uses
 `?:' simply by putting a newline after either character.  However, you
 cannot put a newline in front of either character without using
DONTPRINTYET  backslash continuation ( `awk' Statements Versus Lines
 Statements/Lines.).  If `--posix' is specified (*note Command Line
DONTPRINTYET  backslash continuation ( `awk' Statements Versus Lines
 Statements/Lines.).  If `--posix' is specified ( Command Line

 Options Options.), then this extension is disabled.
Info Catalog
(gawk) Boolean Ops
(gawk) Expressions
(gawk) Function Calls
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