// test_safev.cc   first of sequence, shows UNsafe
//                 test_safe2.cpp adds copy constructor, 'explicit' 
//                 AND operator=
//                 all three are needed to be safe with pointers !!!
//                 test_safev.cpp shows the STL protects you
//                 use STL data structures and get safety that way

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

int main()
{
  cout << "test_safev.cc is SAFE" << endl;
  
  class safev
  {
    public:
      safev(){i=1;}
      safev(safev & x){*this = x;}
      ~safev(){} // do not need 'delete', only objects
      void set(int ii){i=ii;}
      int get(){return i;}
      void set(vector<int> &aa){a=aa;} // vector makes this safe
      void set(int index, int val){ a[index]=val;}
      int get(int index){return a[index];}
    private:
      int i;  // single variables OK
      vector<int> a; // good news, <vector> is safe
  };
  
  vector<int> v1;
  v1.push_back(1);
  v1.push_back(2);
  v1.push_back(3);

  safev U1;
  safev U2;
  //  try{
  //    cout << "illegal index" << U1.get(1) << endl;
  //  }catch(...){cout << "caught illegal index." << endl;}
       
  U1.set(v1);
  cout << "index 1 of U1 is 2== " << U1.get(1) << endl;
  U2=U1; // does <vector> copy GOOD
  cout << "index 1 of U2 is 2== " << U2.get(1) << endl;
  safev U3 = U1; // does <vector> copy GOOD
  cout << "index 1 of U3 is 2== " << U3.get(1) << endl;
  safev U4(U1); // does <vector> copy GOOD
  cout << "index 1 of U4 is 2== " << U4.get(1) << endl;
  
  cout << "now U1.set(1,5) does not change U2, U3 and U4" << endl;
  U1.set(1,5); // set index 1 to value 5
  cout << "index 1 of U1 is 5== " << U1.get(1) << endl;
  cout << "index 1 of U2 is 2== " << U2.get(1) << " GOOD" << endl; 
  cout << "index 1 of U3 is 2== " << U3.get(1) << " GOOD" << endl;
  cout << "index 1 of U4 is 2== " << U4.get(1) << " GOOD" << endl;
   
  cout << "end test_safev" << endl;
  
  return 0;
}
//Output from executing program
// test_safev.cc is SAFE
// index 1 of U1 is 2== 2
// index 1 of U2 is 2== 2
// index 1 of U3 is 2== 2
// index 1 of U4 is 2== 2
// now U1.set(1,5) does not change U2, U3 and U4
// index 1 of U1 is 5== 5
// index 1 of U2 is 2== 2 GOOD
// index 1 of U3 is 2== 2 GOOD
// index 1 of U4 is 2== 2 GOOD
// end test_safev