The correct syntax of this for loop statement

Question

I have a class, something like:

class A : std::queue<double>
{
  [...]

  void foo();
};

Inside foo() I want to iterate through its elements, but I can't seem to get the syntax right.

I assumed it would be something like: for(auto elem : *this) {} but that doesn't work (a long list of compiler errors). What is the correct syntax?

[One should not inherit from standard containers](http://stackoverflow.com/questions/6806173/subclass-inherit-standard-containers). Also, [Queue does not store it's values in order](http://stackoverflow.com/questions/16893530/iterate-through-queue-of-objects-in-order) — Mooing Duck, Apr 30 '15 at 17:01
Actually neither of @MooingDuck's links are relevant. `std::queue` is not `java.util.Queue`, and `std::queue` is not a container. — Ben Voigt, Apr 30 '15 at 17:09

score 1 · Accepted Answer · answered Apr 30 '15 at 16:56

1

The queue can not be iterated directly, however it has a protected member c which is the underlying container. Hence this should work for your case:

for( auto elem : c ) { ... }

Live example

answered Apr 30 '15 at 16:56

Daniel Frey

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That works a treat - thanks. – Lieuwe May 01 '15 at 08:30

The correct syntax of this for loop statement

1 Answers1