#include using namespace std; void swap_doubles_by_ref(double &d1, double &d2){ double temp; temp = d1; d1 = d2; d2 = temp; } void swap_doubles_by_ptr(double *d1, double *d2){ double temp; temp = *d1; *d1 = *d2; *d2 = temp; } int main(){ double e, f; e = 5.0, f = 7.0; cout << e << " " << f << endl; // 5 7 swap_doubles_by_ref(e, f); cout << e << " " << f << endl; // 7 5 e = 5.0, f = 7.0; cout << e << " " << f << endl; // 5 7 swap_doubles_by_ptr(&e, &f); cout << e << " " << f << endl; // 7 5 }