05-cxx-style-sharedptr2.cxx File Reference

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Functions
void	initialize (std::vector< double > &x)
	We pass (as in example 03) a reference to the vector to the functions using it. More...
double	sum_elements (std::vector< double > &x)
int	main ()

Function Documentation

void initialize

(

std::vector< double > &

x

)

We pass (as in example 03) a reference to the vector to the functions using it.

This is possible as long as the function itself does not store the vector in another class.

Examples:

05-cxx-style-sharedptr2.cxx.

Definition at line 17 of file 05-cxx-style-sharedptr2.cxx.

{
  const int n=x.size();
  for (int i=0;i<n;i++) x[i]= 1.0/(double)(1+n-i);
}

double sum_elements

(

std::vector< double > &

x

)

Examples:

05-cxx-style-sharedptr2.cxx.

Definition at line 23 of file 05-cxx-style-sharedptr2.cxx.

{
  double sum=0;
  for (int i=0;i<x.size();i++)sum+=x[i];
  return sum;
}

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int main

(

void

)

Examples:

05-cxx-style-sharedptr2.cxx.

Definition at line 30 of file 05-cxx-style-sharedptr2.cxx.

{
  const int n=12345678;

  // This is a shortcut to the cumbersome statement from
  // Example 04. We have to write the data type only once,
  // as a template argument to std::make_shared<>.
  auto x=std::make_shared<std::vector<double>>(n);
  
  // Dereference the smart pointer here in order to 
  // obtain a reference which can be used as an argumet to the functions.
  initialize(*x);
  double s=sum_elements(*x);
  printf("sum=%e\n",s);

  // The shared pointer is destroyed, reference counter decremented
  // and, as it becomes 0, the allocated memory is released.
  return 0;
}

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