#include <iostream>
using namespace std;

template <typename T>
T sum (T a, T b) {
  return a+b;
}

int main() {
  cout << "10 + 20 = " << sum<int>(10,20) << endl;             // sum<int>
  cout << "10.5 + 20.5 = " << sum<double>(10.5,20.5) << endl;  // sum<double>
  cout << "1.5 + 2 = " << sum<>(1.5,2.0) << endl;              // compiler deducts sum<double>
}