PHP SplHeap rewind() Function

The SplHeap::rewind() function is an inbuilt function in PHP that is used to rewind the iterator to the beginning.

Generally, the Heap Data Structure are of two types:

• Max-Heap: In a Max-Heap the key present at the root node must be greatest among the keys present at all of its children. The same property must be recursively true for all sub-trees in that Binary Tree.
• Min-Heap: In a Min-Heap the key present at the root node must be minimum among the keys present at all of its children. The same property must be recursively true for all sub-trees in that Binary Tree.

Syntax:

void SplHeap::rewind()

Parameters: This function does not accept any parameter.

Return Value: This function does not return any value.

Below programs illustrate the SplHeap::rewind() function in PHP.

Example 1:

PHP

<?php

// Create a new empty Max Heap
$heap = new SplMaxHeap();

$heap->insert('System');
$heap->insert('GFG');
$heap->insert('ALGO');
$heap->insert('C');
$heap->insert('Geeks');
$heap->insert('GeeksforGeeks');

// Use rewind() function
$heap->rewind();

// Display the current element
var_dump($heap->current());

?>

Output:

string(6) "System"

Example 2:

PHP

<?php

// Create a new empty Min Heap
$heap = new SplMinHeap();

$heap->insert('System');
$heap->insert('GFG');
$heap->insert('ALGO');
$heap->insert('C');
$heap->insert('Geeks');
$heap->insert('GeeksforGeeks');

// Use rewind() function
$heap->rewind();

// Display the current element
var_dump($heap);

?>

Output:

object(SplMinHeap)#1 (3) {
  ["flags":"SplHeap":private]=>
  int(0)
  ["isCorrupted":"SplHeap":private]=>
  bool(false)
  ["heap":"SplHeap":private]=>
  array(6) {
    [0]=>
    string(4) "ALGO"
    [1]=>
    string(1) "C"
    [2]=>
    string(3) "GFG"
    [3]=>
    string(6) "System"
    [4]=>
    string(5) "Geeks"
    [5]=>
    string(13) "GeeksforGeeks"
  }
}

Reference: https://www.php.net/manual/en/splheap.rewind.php