C++ #define to create constants and macro

#include <iostream>
using namespace std;
#define AMT1 a+a+a/* w  ww  .ja  v  a  2  s  .  c o m*/
#define AMT2 AMT1 - AMT1
int main()
{
   int a=1;
   cout << "Amount is " << AMT2 << "\n";
   return 0;
}