fig21_35.cpp

来自「《c＋＋大学教程》源码」· C++ 代码 · 共 94 行

// Fig. 21.35: fig21_35.cpp
// Standard library algorithms includes, set_difference, 
// set_intersection, set_symmetric_difference and set_union.
#include <iostream>

using std::cout;
using std::endl;

#include <algorithm>  // algorithm definitions

int main()
{
   const int SIZE1 = 10, SIZE2 = 5, SIZE3 = 20;
   int a1[ SIZE1 ] = { 1, 2, 3, 4, 5, 6, 7, 8, 9, 10 };
   int a2[ SIZE2 ] = { 4, 5, 6, 7, 8 };
   int a3[ SIZE2 ] = { 4, 5, 6, 11, 15 };
   std::ostream_iterator< int > output( cout, " " );

   cout << "a1 contains: ";
   std::copy( a1, a1 + SIZE1, output );
   cout << "\na2 contains: ";
   std::copy( a2, a2 + SIZE2, output );
   cout << "\na3 contains: ";
   std::copy( a3, a3 + SIZE2, output );

   // determine whether set a2 is completely contained in a1
   if ( std::includes( a1, a1 + SIZE1, a2, a2 + SIZE2 ) )
      cout << "\n\na1 includes a2";
   else
      cout << "\n\na1 does not include a2";
      
   // determine whether set a3 is completely contained in a1
   if ( std::includes( a1, a1 + SIZE1, a3, a3 + SIZE2 ) )
      cout << "\na1 includes a3";
   else
      cout << "\na1 does not include a3";

   int difference[ SIZE1 ];

   // determine elements of a1 not in a2
   int *ptr = std::set_difference( a1, a1 + SIZE1, 
      a2, a2 + SIZE2, difference );

   cout << "\n\nset_difference of a1 and a2 is: ";
   std::copy( difference, ptr, output );

   int intersection[ SIZE1 ];

   // determine elements in both a1 and a2
   ptr = std::set_intersection( a1, a1 + SIZE1, 
      a2, a2 + SIZE2, intersection );

   cout << "\n\nset_intersection of a1 and a2 is: ";
   std::copy( intersection, ptr, output );

   int symmetric_difference[ SIZE1 ];
   
   // determine elements of a1 that are not in a2 and 
   // elements of a2 that are not in a1
   ptr = std::set_symmetric_difference( a1, a1 + SIZE1, 
      a2, a2 + SIZE2, symmetric_difference );

   cout << "\n\nset_symmetric_difference of a1 and a2 is: ";
   std::copy( symmetric_difference, ptr, output );

   int unionSet[ SIZE3 ];

   // determine elements that are in either or both sets
   ptr = std::set_union( a1, a1 + SIZE1, 
      a3, a3 + SIZE2, unionSet );

   cout << "\n\nset_union of a1 and a3 is: ";
   std::copy( unionSet, ptr, output );
   
   cout << endl;

   return 0;

} // end main

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