bool SplDoublyLinkedList::valid (void)Parameters:This function takes no parameters.Return Value:This function returns TRUE if the doubly linked list contains more nodes, FALSE otherwise. The following programs illustrate the SplDoublyLinkedList::valid() function in PHP:
Program 1:
// Declare empty SplDoublyLinkedList $list = new SplDoublyLinkedList();
// Use the SplDoublyLinkedList::push() function for
// add elements to 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(); }
?> Exit:1 2 3 8 5
Program 2:
// Declare empty SplDoublyLinkedList $list = new SplDoublyLinkedList();
// Use the SplDoublyLinkedList::add() function
// add an item to the list $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(); }
?> Exit:Welcome to GeeksforGeeks A Computer Science Portal
Link: https://www. php.net/manual/en/spldoublylinkedlist.valid.php
