PHP | SplDoublyLinkedList valid() Function
Last Updated :
21 Nov, 2019
The SplDoublyLinkedList::valid() function is an inbuilt function in PHP which is used to check whether the doubly linked list contains more nodes or not.
Syntax:
bool SplDoublyLinkedList::valid( void )
Parameters: This function does not accept any parameters.
Return Value: This function returns TRUE if the doubly linked list contains any more nodes and FALSE otherwise.
Below programs illustrate the SplDoublyLinkedList::valid() function in PHP:
Program 1:
<?php
$list = new SplDoublyLinkedList();
$list->push(1);
$list->push(2);
$list->push(3);
$list->push(8);
$list->push(5);
$list->rewind();
for($i = 0; $i < 5; $i++) {
if($list->valid())
echo $list->current() . " ";
$list->next();
}
?>
|
Program 2:
<?php
$list = new SplDoublyLinkedList();
$list->add(0, "Welcome");
$list->add(1, "to");
$list->add(2, "GeeksforGeeks");
$list->add(3, "A");
$list->add(4, 'Computer');
$list->add(5, "Science");
$list->add(6, 'Portal');
$list->rewind();
for($i = 0; $i < 7; $i++) {
if($list->valid())
echo $list->current() . " ";
$list->next();
}
?>
|
Output:
Welcome to GeeksforGeeks A Computer Science Portal
Reference: https://www.php.net/manual/en/spldoublylinkedlist.valid.php
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