// test_safe1.cpp  first of sequence, shows UNsafe
//                 test_safe2.cpp adds copy constructor, 'explicit'
//                 AND operator=
//                                all three are needed to be safe !!!

#include <iostream>
using namespace std;

int main()
{
  cout << "test_safe1.cpp is unsafe" << endl;
  
  class unsafe1
  {
    public:
      unsafe1(){i=1; a=0;}
      unsafe1(unsafe1 & x){*this = x;}
      ~unsafe1(){delete a;}
      void set(int ii){i=ii;}
      int get(){return i;}
      void set(int *aa){a=aa;}
      void set(int index, int val){ *(a+index)=val;}
      int get(int index){return *(a+index);}
    private:
      int i;  // single variables OK
      int *a; // bad news, pointer (array)
  };
  
  int d1[3]={1, 2, 3};

  unsafe1 U1;
  unsafe1 U2;
  try{
    cout << "illegal index" << U1.get(1) << endl;
  }catch(...){cout << "caught illegal index." << endl;}
       
  U1.set(d1);
  cout << "index 1 of U1 is 2== " << U1.get(1) << endl;
  U2=U1; // copies bits BAD, should build a copy
  cout << "index 1 of U2 is 2== " << U2.get(1) << endl;
  unsafe1 U3 = U1; // copies bits BAD, should use 'explicit'
  cout << "index 1 of U3 is 2== " << U3.get(1) << endl;
  unsafe1 U4(U1); // copies bits BAD, should use copy constructor
  cout << "index 1 of U4 is 2== " << U4.get(1) << endl;
  
  cout << "now U1.set(1,5) changes U2, U3 and U4 also !!!" << 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) << " BAD" << endl; 
  cout << "index 1 of U3 is 2== " << U3.get(1) << " BAD" << endl;
  cout << "index 1 of U4 is 2== " << U4.get(1) << " BAD" << endl;
   
  cout << "end test_safe1" << endl;
  
  return 0;
}





//Output from executing program
// test_safe1.cpp is unsafe
// caught illegal index.
// 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) changes U2, U3 and U4 also !!!
// index 1 of U1 is 5== 5
// index 1 of U2 is 2== 5 BAD
// index 1 of U3 is 2== 5 BAD
// index 1 of U4 is 2== 5 BAD
// end test_safe1