C++ Operator Overload arithmetic operators work with type Int

#include <iostream>
using namespace std;
#include <process.h>                     //for exit()
class Int/*from  w w w  .j  a  v  a2  s. c o  m*/
{
   private:
   int i;
   public:
   Int() : i(0)                       //no-arg constructor
   {  }
   Int(int ii) : i(ii)                //1-arg constructor
   {  }                            //   (int to Int)
   void putInt()                      //display Int
   { cout << i; }
   void getInt()                      //read Int from kbd
   { cin >> i; }
   operator int()                     //conversion operator
   { return i; }                   //   (Int to int)
   Int operator + (Int i2)            //addition
   { return checkit( long double(i)+long double(i2) ); }
   Int operator - (Int i2)            //subtraction
   { return checkit( long double(i)-long double(i2) ); }
   Int operator * (Int i2)            //multiplication
   { return checkit( long double(i)*long double(i2) ); }
   Int operator / (Int i2)            //division
   { return checkit( long double(i)/long double(i2) ); }
   Int checkit(long double answer)           //check results
   {
      if( answer > 2147483647.0L || answer < -2147483647.0L )
         { cout << "\nOverflow Error\n"; exit(1); }
      return Int( int(answer) );
   }
};
int main()
{
   Int alpha = 20;
   Int beta = 7;
   Int delta, gamma;
   gamma = alpha + beta;                  //27
   cout << "\ngamma="; gamma.putInt();
   gamma = alpha - beta;                  //13
   cout << "\ngamma="; gamma.putInt();
   gamma = alpha * beta;                  //140
   cout << "\ngamma="; gamma.putInt();
   gamma = alpha / beta;                  //2
   cout << "\ngamma="; gamma.putInt();
   delta = 2147483647;
   gamma = delta + alpha;                 //overflow error
   delta = -2147483647;
   gamma = delta - alpha;                 //overflow error
   cout << endl;
   return 0;
}