[C++] 클래스의 기본을 사용한 숫자에 1더하고 빼는것

#include "iostream.h"
class counterclass
{
private : int value;
public : void adder(){value = value + 1; cout << value << endl;}
   void outter(){value = value - 1; cout << value << endl;};
   void setting(int i){value = i;}
};

void main()
{
 int n;

 cout << "\n input number:";
 cin >> n;

 counterclass counter01;
 counter01.setting(n);
 counter01.adder();
 counter01.outter();
}