// two-bit state and operations
//
// #ifndef B2_H_
// #define B2_H_

class B2
{
 private: int b1, b0;

 public: B2(); void print(const char msg[]) const;

  void X(); int M(); // NOT, measure - bit 1

  void CX(); // controlled-NOT on bit 0 controlled by bit 1
};

// #endif // B2_H_
// two-bit state and operations
//
#include <iostream>
// #include "B2.h"
using namespace std;

B2::B2() { b1 = b0 = 0; }

void B2::print(const char msg[]) const
{
  cout << msg << ": " << b1 << " " << b0 << endl;
}

void B2::X() { b1 = !b1; } // NOT, bit 1

void B2::CX() { if( b1) b0 = !b0; } // controlled-NOT on bit 0 controlled by bit 1

int B2::M() { return b1; } // measure, bit 1
#include <iostream>
// #include "B2.h"
using namespace std;

int main()
{
  B2 b; b.print("b");
  b.CX(); b.print("CX");
  b.X(); b.print("X");
  b.CX(); b.print("CX");
  cout << "m1 = " << b.M() << endl;
  b.print("b");
}