#include <iostream>
using namespace std;

/* general format for a function
<return-type> <function name>(<param type1> <param name1>, ...)
{
  <statements> // or code, if you prefer...
  return <value>; // omit if the return-type is void
} */

/* takes in a double, finds the difference of squares, and returns the answer */
double myFunction(double triple)
{
  double answer;
  answer = triple * triple - 1.0;
  return answer;
}

void secondFunction(double &triple)
{
  triple = triple * triple - 1.0;
}


int main()
{
  double squares, userInput;
  
  cout << "What number do you want to try? ";
  cin >> userInput;
  
  // now we call the function - there is no need to re-specify return or parameter types
  squares = myFunction(userInput);
  cout << "The difference of squares of " << userInput << " is " << squares << endl;
  
  // now we try by reference
  secondFunction(userInput);
  cout << "By reference, we get " << userInput << endl;
  
  return 0;
}