// Joe Shinnerl (shinnerl@ucla.edu), CS 31
// Example:  simple sets of integers
//
// To do: 
//  Set(int data0[], size0);      // Initializing constructor.
//  friend Set setUnion(const Set&, const Set&);
//
// Note: No need for Set(const Set& ); the "automatic" Copy Constructor is OK!

#include <cassert>
#include <iostream>
using namespace std;

class Set{

  public:
    Set() : size(0) {}            // Default constructor.
    Set(int data0[], int size0);  // Initializing constructor.

    bool has( int ) const;      // membership checker
    void join( int );          // membership maker -- union with one more int.
    void assign( const Set& );   // assignment

    friend Set setIntersect(const Set&, const Set&);
    friend Set setUnion(const Set&, const Set&);

    void get( istream& );         // stream input 
    void put( ostream& ) const;   // stream output

  private:
    static const int MAX_SIZE = 20;
    int data[ MAX_SIZE ];
    int size;
};

bool Set::has( int value ) const {
   bool answer = false;
   for (int i=0; i< size && !answer; ++i)
     if (data[i] == value )
        answer = true;
   return answer;
}

void Set::join( int value ) {     // Corrected 10:15am 2/20/03
   if ( size < MAX_SIZE ){
      if ( !has(value) )
         data[size++] = value ;
   }
   else
      cerr << "Error in Set::join(): "
           << "storage size limit exceeded.\n";
}

void Set::assign( const Set& rhs ){   // assignment
   size = rhs.size;
   for (int i = 0; i < size; ++i)
     data[i] = rhs.data[i];
}

void Set::get( istream& is ){
   is >> size;
   if ( size > 0 && size <= MAX_SIZE ){
      for (int i = 0; i < size; ++i)
        is >> data[i];
   }
   else 
      cerr << "Set::get() input error: set size out of range.\n";
}

void Set::put( ostream& os ) const {   // Note: not symmetric w.r.t. get().
   for (int i = 0; i < size; ++i)
      os << data[i] << "  ";
}

Set setIntersect(const Set& A, const Set& B){
  // Quadratic-time solution for unsorted sets
  Set C;
  for (int i = 0; i < A.size; ++i)
       if (B.has( A.data[i] ))
            C.join( A.data[i] );
  return C;
}

void menu(){
   cout << "Enter \n"
        << "   E    to ENTER set A or set B by keyboard input \n"
        << "   V    to VIEW all sets  \n"
        << "   R    to REPLACE a set  \n"
        << "   I    to find the INTERSECTION of A and B  \n"
        << "   U    to find the UNION of A and B  \n"
        << "   Q    to QUIT  \n" << endl;
}

void prompt() { cout << "\nEVRIUQ > "; }

int main(){
 Set A,B,C;
 menu();
 char ch;
   do{
      prompt();
      cin >> ch;
      switch (ch){
         case 'e': case 'E': {
            cout << "A or B? ";
            cin >> ch;
            if (ch == 'A')   A.get(cin); 
            else if (ch == 'B') B.get(cin);
            break;
         }
         case 'v': case 'V':  
            cout << " A = "; A.put(cout);  cout << endl;
            cout << " B = "; B.put(cout); cout << endl;
            cout << " C = "; C.put(cout); cout << endl;
         case 'i': case 'I':  
           C.assign( setIntersect(A, B) );
      }
   } while (ch != 'q' && ch != 'Q' );
 return 0;
}