Question

Assume we have two sequences of values S1 containing 1, 5, 3, 6, 7, 8 while S2 containing 2, 5, 6, 9, 7. We store these two sequences as sets and perform a set intersection and set difference. Write C++ code to do that respectively.

Answer 1

C++ Program:

#include <iostream>
#include <set>
#include <iterator>

using namespace std;

int main()
{
   // empty set containers
   set <int, greater <int> > set1;  
   set <int, greater <int> > set2;
   set <int, greater <int> > setintersection;
   set <int, greater <int> > setdifference;

   // inserting elements into set1
   set1.insert(1);
   set1.insert(5);
   set1.insert(3);
   set1.insert(6);
   set1.insert(7);
   set1.insert(8);
  
   // inserting elements into set2
   set2.insert(2);
   set2.insert(5);
   set2.insert(6);
   set2.insert(9);
   set2.insert(7);
  
   //Set intersection of two sets give a set
   //with the elements present in both sets
   //Finding set intersection
   set <int, greater <int> > :: iterator itr1;
   for (itr1 = set1.begin(); itr1 != set1.end(); ++itr1)
   {
       set <int, greater <int> > :: iterator itr2;
       for(itr2 = set2.begin(); itr2 != set2.end(); ++itr2)
       {
       //Find a match, add it to intersection set
       if(*itr1 == *itr2)
       setintersection.insert(*itr1);
       }
  
   }

   // printing set intersection
   set <int, greater <int> > :: iterator itr3;
   cout << "\nThe set intersection is : ";
   for (itr3 = setintersection.begin(); itr3 != setintersection.end(); ++itr3)
   {
       cout << *itr3 << '\t';
   }
   cout << endl;
  
   //Set Difference of two sets gives a set
   //with elements present in first set and not present in second set
   //Finding set difference
   set <int, greater <int> > :: iterator itr4;
   for (itr4 = set1.begin(); itr4 != set1.end(); ++itr4)
   {
   int flag=0;
       set <int, greater <int> > :: iterator itr2;
       for(itr2 = set2.begin(); itr2 != set2.end(); ++itr2)
       {
       if(*itr4 == *itr2){
       flag=1;
       itr2=set2.end();
       }
       }
       //Not find a match, add it to difference set
   if(flag==0)
   setdifference.insert(*itr4);
   }

   // printing set difference
   set <int, greater <int> > :: iterator itr5;
   cout << "\nThe set difference is : ";
   for (itr5 = setdifference.begin(); itr5 != setdifference.end(); ++itr5)
   {
       cout << *itr5 << '\t';
   }
   cout << endl;

   return 0;

}

Code Screenshots:

Output Screenshot: