Pass by reference

gistfile1.cpp

int main() {
  int foo = 5;

  bar(foo);
  if(foo == 5) {
    cout << "foo not changed" << endl;
  }

  passByReference(foo);
  if(foo == 6) {
    cout << "foo changed to 6" << endl;
  }
}

void bar(int a){
  a = 4;
}

void passByReference(int &b){
  a = 6
}