C++ template function Get absolute value

#include <iostream>
using namespace std;
template <class T>             //function template
T abs(T n)/*from w w  w.j  a  va  2 s . c om*/
{
   return (n < 0) ? -n : n;
}
int main()
{
   int int1 = 5;
   int int2 = -6;
   long lon1 = 70000L;
   long lon2 = -80000L;
   double dub1 = 9.95;
   double dub2 = -10.15;
   //calls instantiate functions
   cout << "\nabs(" << int1 << ")=" << abs(int1);  //abs(int)
   cout << "\nabs(" << int2 << ")=" << abs(int2);  //abs(int)
   cout << "\nabs(" << lon1 << ")=" << abs(lon1);  //abs(long)
   cout << "\nabs(" << lon2 << ")=" << abs(lon2);  //abs(long)
   cout << "\nabs(" << dub1 << ")=" << abs(dub1);  //abs(double)
   cout << "\nabs(" << dub2 << ")=" << abs(dub2);  //abs(double)
   cout << endl;
   return 0;
}