#include <iostream>
 
void swapPointers(double*& num1, double*& num2) {
  double* temp = num1;
  num1 = num2;
  num2 = temp;
}
 
int main() {
    double a = 1.0f;
    double b = 5.0f;
    double* pa = &a;
    double* pb = &b;
    swapPointers(pa, pb);
    std::cout << *pa << " " << *pb << std::endl;
    std::cout << a << " " << b << std::endl;
}