Directly access element of a structure

Question

Is it possible to make a structure mimic one of its elements? Example:

struct example_struct
{
  double x[2];
  double operator[](int i){return x[i];};
}
struct example_struct var;

Now, assuming var.x has somehow been initialised, expressions like std::cout<<var[1]; clearly work, but what should I do to make expressions like var[1]=3; work?

Make your return type `double&` and find a [solid C++ book](https://stackoverflow.com/questions/388242/the-definitive-c-book-guide-and-list) — scohe001, Oct 16 '17 at 17:49
http://www.learncpp.com/cpp-tutorial/98-overloading-the-subscript-operator/ — zzxyz, Oct 16 '17 at 17:52
`struct example_struct var;` is C. You don't need struct here. — , Oct 16 '17 at 17:56

score 4 · Answer 1 · edited Oct 16 '17 at 17:53

4

You need to return a reference, not a copy in order for var[1]=3 to work.

struct example_struct
{
   double x[2];
   double& operator[](int i) return x[i];};
}

edited Oct 16 '17 at 17:53

scohe001

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answered Oct 16 '17 at 17:49

lcs

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Directly access element of a structure

1 Answers1