//a simple class for binary number by tsaiwn@csie.nctu.edu.tw
#include <iostream.h>
class BIN{
    protected: long data;   // so that can be accessed by derived class
    friend ostream& operator<< (ostream&, const BIN&);
    public:
        BIN(){data=0;};
        BIN(long);
        BIN(BIN& x)   // copy constructor
        { data = 3; cout << "(copy)";    // data = x.data;
        }
};
BIN::BIN(long x) { data=x; }
//////
// new class inherit from BIN  (i.e., we reuse BIN to build a new class)
class BINREAL: public BIN{
     float fdata;
    public:
        BINREAL(){data=0; setBin( ); };
        BINREAL(float x) { fdata=x; setBin( ); }
        void setBin( ) {
            long * ptemp = (long *) &fdata;
            data = *ptemp;   // data = ptemp[0];
        }
};
int main()
{     float m;
      BINREAL y;
   m=1234567.3;   // actually it is 1234567.25
   y=m;
   cout << "m=" << m;
   cout << "=== y =" << y << endl;;
   BIN x=y; // will call copy constructor
   cout << "\t\t x= " << x << " Note\n";
   cout << "What if the copy constructor is removed?\n\n";
   while(m){
      cout << "Input a float number:";
      cin >> m;
      y = m;
      cout << "===" << y;
      cout << " = " << m << endl;
   }
   cout << "Thank you for using AT&T:-)\n";
}
ostream& operator<< (ostream& oo, const BIN& x)
{
        long tmp,i;
        tmp = x.data;
        for(i=1; i<=32; i++){
           if(tmp<0) oo << 1;
           else oo << 0;
           if(i%4 == 0) cout << " ";   // Ohh .. bug?
           tmp = tmp << 1;
        }
        return oo;
}
/*** answer:
10:24am magpie::oop/> g++ binfloat.cpp
10:25am magpie::oop/> ./a.out
m=1.23457e+06=== y =0100 1001 1001 0110 1011 0100 0011 1010
(copy)           x= 0000 0000 0000 0000 0000 0000 0000 0011  Note
What if the copy constructor is removed?

Input a float number:1234567.2
===0100 1001 1001 0110 1011 0100 0011 1010  = 1.23457e+06
Input a float number:0.25
===0011 1110 1000 0000 0000 0000 0000 0000  = 0.25
Input a float number:0.5
===0011 1111 0000 0000 0000 0000 0000 0000  = 0.5
Input a float number:1.0
===0011 1111 1000 0000 0000 0000 0000 0000  = 1
Input a float number:1.25
===0011 1111 1010 0000 0000 0000 0000 0000  = 1.25
Input a float number:1.75
===0011 1111 1110 0000 0000 0000 0000 0000  = 1.75
Input a float number:1.875
===0011 1111 1111 0000 0000 0000 0000 0000  = 1.875
Input a float number:0
===0000 0000 0000 0000 0000 0000 0000 0000  = 0
Thank you for using AT&T:-)
10:26am magpie::oop/>
*******************/