fig20_37.cpp

里面有很多关于编程的实用例子

// Fig. 20.37: fig20_37.cpp
// Standard Library algorithms push_heap, pop_heap, 
// make_heap and sort_heap.
#include <iostream>
using std::cout;
using std::endl;

#include <algorithm>
#include <vector>
#include <iterator> 

int main()
{
   const int SIZE = 10;
   int a[ SIZE ] = { 3, 100, 52, 77, 22, 31, 1, 98, 13, 40 };
   std::vector< int > v( a, a + SIZE ); // copy of a
   std::vector< int > v2;
   std::ostream_iterator< int > output( cout, " " );

   cout << "Vector v before make_heap:\n";
   std::copy( v.begin(), v.end(), output );

   std::make_heap( v.begin(), v.end() ); // create heap from vector v
   cout << "\nVector v after make_heap:\n";
   std::copy( v.begin(), v.end(), output );
   
   std::sort_heap( v.begin(), v.end() ); // sort elements with sort_heap
   cout << "\nVector v after sort_heap:\n";
   std::copy( v.begin(), v.end(), output );

   // perform the heapsort with push_heap and pop_heap
   cout << "\n\nArray a contains: ";
   std::copy( a, a + SIZE, output ); // display array a
   cout << endl;

   // place elements of array a into v2 and 
   // maintain elements of v2 in heap
   for ( int i = 0; i < SIZE; i++ ) 
   {
      v2.push_back( a[ i ] );
      std::push_heap( v2.begin(), v2.end() );      
      cout << "\nv2 after push_heap(a[" << i << "]): ";
      std::copy( v2.begin(), v2.end(), output );
   } // end for
   
   cout << endl;

   // remove elements from heap in sorted order
   for ( unsigned int j = 0; j < v2.size(); j++ ) 
   {
      cout << "\nv2 after " << v2[ 0 ] << " popped from heap\n";
      std::pop_heap( v2.begin(), v2.end() - j );
      std::copy( v2.begin(), v2.end(), output );
   } // end for

   cout << endl;
   return 0;
} // end main

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