Control Flow - The Java Programming Language - page 354

except that in a for statement the update-expression is always executed
if a continue is encountered in the loop body (see " continue " on page
244 ) .
The initialization and update parts of a for loop can be comma-separated
lists of expressions. The expressions separated by the commas are, like
most operator operands, evaluated from left-to-right. For example, to
march two indexes through an array in opposite directions, the following
code would be appropriate:
for (i = 0, j = arr.length - 1; j >= 0; i++, j--) {
// ...
}
The initialization section of a for loop can also be a local variable declar-
ation statement, as described on page 170 . For example, if i and j are
not used outside the for loop, you could rewrite the previous example
as:
for (int i = 0, j = arr.length - 1; j >= 0; i++, j--) {
// ...
}
If you have a local variable declaration, however, each part of the ex-
pression after a comma is expected to be a part of that local variable
declaration. For example, if you want to print the first MAX members of a
linked list you need to both maintain a count and iterate through the list
members. You might be tempted to try the following:
for (int i = 0, Cell node = head; // INVALID
i < MAX && node != null;
i++, node = node.next)
{
System.out.println(node.getElement());
}