//This file is symphony.h.
#ifndef SYMPHONYH
#define SYMPHONYH

class symphony {
	int i;
	void install(int n);
public:
	symphony(int initial_i = 1) {install(initial_i);}
	operator int() const {return i;}

	symphony& operator=(int n)  {install(n);     return *this;}

	symphony& operator+=(int n) {install(i + n); return *this;}
	symphony& operator-=(int n) {install(i - n); return *this;}

	symphony& operator++()      {install(i + 1); return *this;}
	symphony& operator--()      {install(i - 1); return *this;}

	const symphony operator++(int){const symphony old=*this; ++*this;return old;}
	const symphony operator--(int){const symphony old=*this; --*this;return old;}
};
#endif