Do Statement (The GNU Awk User’s Guide)
Next: For Statement, Previous: While Statement, Up: Statements [Contents][Index]
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.