#include <iostream>
#include <math.h>
using namespace std;

double f(double x) // function return a value of type double
{
  double y = 1.2 * x*x - 3.*x + 1.; 
  return y;  // returned value
}

int main()
{
  cout << f(0.1) << endl; // calling function f with parameter 0.1
}