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make_heap
Converts a range into a heap
Definition
The make_heap() algorithm is defined in the standard header <algorithm> and in the nonstandard backward-compatibility header <algo.h>.Interface
#include <algorithm> template < class RandomAccessIterator > void make_heap( RandomAccessIterator first, RandomAccessIterator last ); template < class RandomAccessIterator, class BinaryPredicate > void make_heap( RandomAccessIterator first, RandomAccessIterator last, BinaryPredicate comp );Parameters:
| Parameter | Description |
|---|---|
| first | A random-access iterator addressing the position of the first element in the range to be converted into a heap |
| last | A random-access iterator addressing the position one past the final element in the range to be converted into a heap |
| comp | User-defined predicate function object that defines sense in which one element is less than another. A binary predicate takes two arguments and returns true when satisfied and false when not satisfied |
Description
Make_heap() function reorders the elements betweenfi rst and last in order to create a heap.
The first version compares objects using operator< and the second compares objects using a function object comp.References
Example:
Example - make_heap algorithm
Problem
This program illustrates the use of the STL make_heap() algorithm (default
version) to convert an arbitrary vector of integers into a heap.
Workings
#include <iostream> #include <vector> #include <algorithm> using namespace std; int main() { int a[] = {25, 17, 36, 2, 3, 100, 1, 19, 7}; vector<int> v(a, a+9); cout <<"\nHere are the values in the vector:\n"; for (vector<int>::size_type i=0; i<v.size(); i++) cout <<v.at(i)<<" "; cout <<"\nNow we make these values into a (maximum) heap."; make_heap(v.begin(), v.end()); cout <<"\nHere are the revised contents of the vector:\n"; for (vector<int>::size_type i=0; i<v.size(); i++) cout <<v.at(i)<<" "; return 0; }
Solution
Output:
Here are the values in the vector:
25 17 36 2 3 100 1 19 7 Now we make these values into a (maximum) heap. Here are the revised contents of the vector:
100 19 36 17 3 25 1 2 7
25 17 36 2 3 100 1 19 7 Now we make these values into a (maximum) heap. Here are the revised contents of the vector:
100 19 36 17 3 25 1 2 7
References
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