///////////////////////////////////////////////////////////////
//  exmp2d.cpp - passing pointers by value                   //
//  Jim Fawcett, ELE591\791, Su'99                           //
//  build: cl /GX exmp2ld.cpp                                //
///////////////////////////////////////////////////////////////

#include <iostream>
#include <fstream>
#include <string>
using namespace std;

//----< demonstrate pass by value >----------------------------

void passByValue(double **ppDouble) {

  cout << "\n\n  inside passByValue(...)";
  double *pDouble = new double;
  if(!pDouble)
    throw "\n  memory allocation failure\n\n";

  *pDouble = 2.5;
  *ppDouble = pDouble;    // changing poiner address
  cout << "\n  value of *ppDouble is " << *ppDouble;
  cout << "\n  value pointed to by ppDouble is " << **ppDouble;
}

//----< test >-------------------------------------------------

void main() {

  cout << "\n  before calling passByValue(...)";
  double target = -1.0;
  double *pTarget = &target;
  double **ppDouble = &pTarget;
  cout << "\n  value of *ppDouble is " << *ppDouble;
  cout << "\n  value pointed to by ppDouble is " << **ppDouble;

  passByValue(ppDouble);

  cout << "\n\n  after calling passByValue(...)";
  cout << "\n  value of *ppDouble is " << *ppDouble;
  cout << "\n  value pointed to by ppDouble is " << **ppDouble 
       << "\n\n";
}