Syntax:mixedpublic DsPriorityQueue::peek (void)
Parameters: This function takes no parameters.Return Value:This function returns the value present at the beginning of this PriorityQueue. The return type of the function is mixed and depends on the type of the value stored in the PriorityQueue.Exception : This function throws a exceptionUnderflowException if the PriorityQueue is empty. The programs below illustrate Ds / PriorityQueue::peek(): Program 1:
// Declare a new PriorityQueue $pq = new DsPriorityQueue();
// Add items to PriorityQueue $pq -> push ( "One" , 1); $pq -> push ( "Two" , 2); $pq -> push ( "Three" , 3); echo " PriorityQueue is: " ; print_r ( $pq );
// Get element in front echo "Element at front is:" ; print_r ( $pq -> peek());
?> Exit:PriorityQueue is: DsPriorityQueue Object ([0] = > Three [1] = > Two [2] = > One) Element at front is: Three
Program 2:
// Declare a new PriorityQueue $pq = new DsPriorityQueue(); echo " PriorityQueue is: " ; print_r ( $pq );
// Get element in front echo "Element at front is:" ; print_r ( $pq -> peek());
?> Exit:PHP Fatal error : Uncaught UnderflowException
Link: http : //php.net/manual/en/ds-priorityqueue.peek.php
