for each in GCC and GCC version

Question

hi

how can I use for each loop in GCC?

and how can i get GCC version? (in code)

Answer 1

Use a lambda, e.g.

// C++0x only.
std::for_each(theContainer.begin(), theContainer.end(), [](someType x) {
    // do stuff with x.
});

The range-based for loop is not supported by GCC as of version 4.6.

// C++0x only, not widely supported
for (auto x : theContainer) {
   // do stuff with x.
}

The "for each" loop syntax is an MSVC extension. It is not available in other compilers.

// MSVC only
for each (auto x in theContainer) {
  // do stuff with x.
}

But you could just use Boost.Foreach. It is portable and available without C++0x too.

// Requires Boost
BOOST_FOREACH(someType x, theContainer) {
  // do stuff with x.
}

---

See How do I test the current version of GCC ? on how to get the GCC version.

Answer 2

there is also the traditionnal way, not using C++0X lambda. The <algorithm> header is designed to be used with objects that have a defined operator parenthesis. ( C++0x lambdas are only of subset of objects that have the operator () )

struct Functor
{
   void operator()(MyType& object)
   {
      // what you want to do on objects
   }
}

void Foo(std::vector<MyType>& vector)
{
  Functor functor;
  std::for_each(vector.begin(), vector.end(), functor);
}

see alogrithm header reference for a list of all c++ standard functions that work with functors and lambdas.