// two-qubit state and operations
//
// #ifndef Q2_H_
// #define Q2_H_

class Q2
{
 private: double a00, a01, a10, a11;

 public: Q2(); void print(const char msg[]) const;

};

// #endif // Q2_H_
// two-qubit state and operations
//
#include <iostream>
// #include "Q2.h"
using namespace std;

Q2::Q2() { a00 = 1;  a01 = a10 = a11 = 0; }

void Q2::print(const char msg[]) const
{
  cout << msg << ":" << endl;
  cout << " 00  " << a00*a00 << "   (" << a00 << ")" << endl;
  cout << " 01  " << a01*a01 << "   (" << a01 << ")" << endl;
  cout << " 10  " << a10*a10 << "   (" << a10 << ")" << endl;
  cout << " 11  " << a11*a11 << "   (" << a11 << ")" << endl;
}

// test Q2
//
#include <iostream>
// #include "Q2.h"
using namespace std;

int main()
{
  Q2 q; q.print("q");
}