引用：&(reference)與間接引用：*(dereference)

#include <iostream>
using namespace std;

int addition (int a, int b)
{
  int r;
  r=a+b;
  return r;
}

int main ()
{
  int x=5, y=3, z;
  z = addition (x,y); 
  cout << "The result is " << z;//The result is 8
}

// passing parameters by reference
#include <iostream>
using namespace std;

void duplicate (int& a, int& b, int& c)
{
  a*=2;
  b*=2;
  c*=2;
}

int main ()
{
  int x=1, y=3, z=7;
  duplicate (x, y, z);
  cout << "x=" << x << ", y=" << y << ", z=" << z; //x=2, y=6, z=14
  return 0;
}