sort_heap function in C++
The sort_heap( ) is an STL algorithm which sorts a heap within the range specified by start and end. Sorts the elements in the heap range [start, end) into ascending order.
The second form allows you to specify a comparison function that determines when one element is less than another.
Defined in header
It has two versions, which are defined below:.
1. Comparing elements using “<":
Syntax:
template void sort_heap(RandIter start, RandIter end); start, end : the range of elements to sort Return Value: Since, return type is void, so it doesnot return any value.
Implementation
template void sort_heap( RandIter start, RandIter end ); { while (start != end) std::pop_heap(start, end--); }
2. By comparing using a pre-defined function:
Syntax:
template void sort_heap(RandIter start, RandIter end, Comp cmpfn); start, end : the range of elements to sort comp: comparison function object (i.e. an object that satisfies the requirements of Compare) which returns ?true if the first argument is less than the second. Return Value : Since, its return type is void, so it doesnot return any value.
Implementation
template void sort_heap( RandIter start, RandIter end, Comp cmpfn ); { while (start != end) std::pop_heap(start, end--, cmpfn); }
// CPP program to illustrate // std::sort_heap #include <iostream> #include <algorithm> #include <vector> using namespace std; int main() { vector< int > v = {8, 6, 2, 1, 5, 10}; make_heap(v.begin(), v.end()); cout << "heap: " ; for ( const auto &i : v) { cout << i << ' ' ; } sort_heap(v.begin(), v.end()); std::cout <<endl<< "now sorted: " ; for ( const auto &i : v) { cout << i << ' ' ; } std::cout <<endl; } |
Output:
heap: 10 6 8 1 5 2 now sorted: 1 2 5 6 8 10
Another Example :
// CPP program to illustrate // std::sort_heap #include <vector> #include <algorithm> #include <functional> #include <iostream> int main( ) { using namespace std; vector < int > vt1, vt2; vector < int >::iterator Itera1, Itera2; int i; for ( i = 1 ; i <=5 ; i++ ) vt1.push_back( i ); random_shuffle( vt1.begin( ), vt1.end( ) ); cout << "vector vt1 is ( " ; for ( Itera1 = vt1.begin( ) ; Itera1 != vt1.end( ) ; Itera1++ ) cout << *Itera1 << " " ; cout << ")" << endl; sort_heap (vt1.begin( ), vt1.end( ) ); cout << "heap vt1 sorted range: ( " ; for ( Itera1 = vt1.begin( ) ; Itera1 != vt1.end( ) ; Itera1++ ) cout << *Itera1 << " " ; cout << ")" << endl; } |
Output:
vector vt1 is ( 5 4 2 3 1 ) heap vt1 sorted range: ( 1 2 3 4 5 )