C++ Program to Implement Set in STL

Set is abstract data type in which each element has to be unique, because the value of the element identifies it. The value of the element cannot be modified once it is added to the set, but it is possible to remove and add the modified value of that element.
Functions used here:
   st.size() = Returns the size of set.
   st.insert() = It is used to insert elements to the set.
   st.erase() = To delete the element from the set.
   st.find() = Returns an iterator to the search element in the set if found, else returns the iterator to
   end. st.begin() = Returns an iterator to the first element in the set.
   st.end() = Returns an iterator to the last element in the set.
#include <iostream>
#include <set>
#include <string>
#include <cstdlib>
using namespace std;
int main() {
   set<int> st;
   set<int>::iterator it;
   int c, i;
   while (1) {
      cout<<"1.Size of the Set"<<endl;
      cout<<"2.Insert Element into the Set"<<endl;
      cout<<"3.Delete Element of the Set"<<endl;
      cout<<"4.Find Element in a Set"<<endl;
      cout<<"5.Display the set: "<<endl;
      cout<<"6.Exit"<<endl;
      cout<<"Enter your Choice: ";
      cin>>c;
      switch(c) {
         case 1:
            cout<<"Size of the Set: ";
            cout<<st.size()<<endl;
         break;
         case 2:
            cout<<"Enter value to be inserted: ";
            cin>>i;
            st.insert(i);
         break;
         case 3:
            cout<<"Enter the element to be deleted: ";
            cin>>i;
            st.erase(i);
         break;
         case 4:
            cout<<"Enter the element to be found: ";
            cin>>i;
            it = st.find(i);
            if (it != st.end())
               cout<<"Element "<<*it<<" found in the set" <<endl;
            else
               cout<<"No Element Found"<<endl;
         break;
         case 5:
            cout<<"Displaying Set by Iterator: ";
            for (it = st.begin(); it != st.end(); it++) {
               cout << (*it)<<" ";
            }
            cout<<endl;
         break;
         case 6:
            exit(1);
         break;
         default:
            cout<<"Wrong Choice"<<endl;
      }
   }
return 0;
}
1.Size of the Set
2.Insert Element into the Set
3.Delete Element of the Set
4.Find Element in a Set
5.Display the set:
6.Exit

Enter your Choice: 1
Size of the Set: 0
1.Size of the Set
2.Insert Element into the Set
3.Delete Element of the Set
4.Find Element in a Set
5.Display the set:
6.Exit


Enter your Choice: 2
Enter value to be inserted: 1
1.Size of the Set
2.Insert Element into the Set
3.Delete Element of the Set
4.Find Element in a Set
5.Display the set:
6.Exit

Enter your Choice: 2
Enter value to be inserted: 7
1.Size of the Set
2.Insert Element into the Set
3.Delete Element of the Set
4.Find Element in a Set
5.Display the set:
6.Exit

Enter your Choice: 2
Enter value to be inserted: 6
1.Size of the Set
2.Insert Element into the Set
3.Delete Element of the Set
4.Find Element in a Set
5.Display the set:
6.Exit

Enter your Choice: 2
Enter value to be inserted: 4
1.Size of the Set
2.Insert Element into the Set
3.Delete Element of the Set
4.Find Element in a Set
5.Display the set:
6.Exit

Enter your Choice: 3
Enter the element to be deleted: 1
1.Size of the Set
2.Insert Element into the Set
3.Delete Element of the Set
4.Find Element in a Set
5.Display the set:
6.Exit

Enter your Choice: 4
Enter the element to be found: 7
Element 7 found in the set
1.Size of the Set
2.Insert Element into the Set
3.Delete Element of the Set
4.Find Element in a Set
5.Display the set:
6.Exit
Enter your Choice: 6
Exit code: 1