output.cpp

#include <iostream>
#include <fstream>

using namespace std;

// Generic print function that takes an output stream.
// Can be used to print to the screen by passing cout.
// Can be used to print to a file by passing a file stream.
void printSomething(ostream &out, string somethingToSay) {
  out << "Something cool:" << somethingToSay << endl;
}

int main() {
  // Print to the screen
  printSomething(cout, "hey there");

  // Writes the same thing to a file
  ofstream myfile;
  myfile.open("example.txt");
  printSomething(myfile, "hey there");
  myfile.close();

  return 0;
}