for each in GCC and GCC version

Question

how can I use for each loop in GCC?

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

I don't see any relationship between the two questions... – kennytm Aug 21 '10 at 10:56 — kennytm, Aug 21 '10 at 10:56

score 26 · Accepted Answer · edited May 23 '17 at 11:53

26

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 supported by GCC since 4.6.

// C++0x only
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.

edited May 23 '17 at 11:53

Community

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answered Aug 21 '10 at 10:57

kennytm

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no, in C++0x format. like as VC++ 2010: for each( auto it in vec) { cout << it << endl; } – user335870 Aug 21 '10 at 10:59
1

@user: `for each` is not C++0x. – kennytm Aug 21 '10 at 11:10
1

Is `for each` C++cli, or is it an extension to raw C++? – Johannes Schaub - litb Aug 21 '10 at 11:51
@Johannes std::for_each(,,) is currently part of the ISO Standard C++, defined in 2003. It is not an extension, it is part of the currently available features in C++. One has to include the `` header. – Stephane Rolland Aug 21 '10 at 12:24
GCC 4.6 was [released](http://gcc.gnu.org/gcc-4.6/) with [range-based for](http://gcc.gnu.org/gcc-4.6/changes.html#cplusplus). – Tobu Jun 11 '11 at 15:17
This answer should be fixed. GCC as of version 4.6 DOES support range-based for. – Ricky65 Aug 17 '11 at 23:34

Stephane Rolland · Answer 2 · 2012-05-04T11:30:52.513

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

for each in GCC and GCC version

2 Answers2