Control Flow Statements

if ( expr)  statement [ else statement]
if ( subscript  in  array)  statement [ else  statement]
while ( expr)  statement
for ( expr ;  expr ;  expr )  statement
for (  var  in  array )  statement
do statement  while ( expr)
break
continue
next
exit [ expr]
return [ expr]

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

awk '{ for (i = 1; i <= 3; i++)
          print $i}'

awk '{ i = 1
       while (i <= 5) {
           print $i
           i++
       }
}'