File: gawk.info,  Node: Do Statement,  Next: For Statement,  Prev: While Statement,  Up: Statements

7.4.3 The 'do'-'while' Statement
--------------------------------

The 'do' loop is a variation of the 'while' looping statement.  The 'do'
loop executes the BODY once and then repeats the BODY as long as the
CONDITION is true.  It looks like this:

     do
       BODY
     while (CONDITION)

   Even if the CONDITION is false at the start, the BODY executes at
least once (and only once, unless executing BODY makes CONDITION true).
Contrast this with the corresponding 'while' statement:

     while (CONDITION)
         BODY

This statement does not execute the BODY even once if the CONDITION is
false to begin with.  The following is an example of a 'do' statement:

     {
         i = 1
         do {
             print $0
             i++
         } while (i <= 10)
     }

This program prints each input record 10 times.  However, it isn't a
very realistic example, because in this case an ordinary 'while' would
do just as well.  This situation reflects actual experience; only
occasionally is there a real use for a 'do' statement.