#include <iostream.h>

void swap(double *, double *);     // function prototype

int main()
{
  double firstnum = 20.5, secnum = 6.25;


  cout << "\nThe value stored in firstnum is: " << firstnum << endl;
  cout << "The value stored in secnum is: " << secnum << "\n\n";

  swap(&firstnum, &secnum);          // call swap

  cout << "The value stored in firstnum is now: " 
       << firstnum <<  endl;
  cout << "The value stored in secnum is now: " 
       << secnum << endl;

  return 0;
}

// this function swaps the values in its two arguments
void swap(double *nm1Addr, double *nm2Addr)
{
  double temp;

  temp = *nm1Addr;           // save firstnum's value
  *nm1Addr = *nm2Addr;       // move secnum's value in firstnum
  *nm2Addr = temp;           // change secnum's value

  return;
}