c++ value/pointer/reference example

test.cpp

#include <iostream>
using namespace std;

void print_by_value(string message) { cout << message << endl; }
void print_by_pointer(string *message) { cout << *message << endl; }
void print_by_reference(string &message) { cout << message << endl; }

int main() {
  string message = "whatever";
  print_by_value(message);
  print_by_pointer(&message);
  print_by_reference(message);
}