Foreach.h File Reference

Macro for iterating over all elements in a container. More...

#include <boost/foreach.hpp>
#include <boost/version.hpp>
#include <boost/typeof/typeof.hpp>

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Namespaces
	boost

Macros
#define	foreach   BOOST_FOREACH
	This macro provides a more convenient name for BOOST_FOREACH. More...
#define	foreach_reverse   BOOST_REVERSE_FOREACH
	This macro provides a more convenient name for BOOST_REVERSE_FOREACH. More...
#define	foreachIt(var, container)   for(auto var=container.begin();var!=container.end();++var)
	This macro provides a more convenient way for iterating over containers or other sequences that provide iterator concepts. More...

Detailed Description

Macro for iterating over all elements in a container.

Author

Erik Einhorn

Date

2010/05/20

Macro Definition Documentation

foreach

#define foreach   BOOST_FOREACH

This macro provides a more convenient name for BOOST_FOREACH.

The macro allows a PERL-or JAVA-like "foreach" construct that automates the iteration over containers or other sequences that provide iterator concepts.

Examples:

std::list<int> list_int;
...
foreach(int i, list_int )  // i is accessed by value here
{
     // do something with i
}

foreach(const int& i, list_int ) // i is accessed by const reference
{                                 // here and avoids unnecessary copying.
     // do something with i
}

foreach(int& i, list_int ) // i is accessed by reference here
{
     i = ... // change the value in the container
}

// the same also works for C-strings and std::strings:
std::string str( "Hello, world!" );
foreach(char ch, str)
{
    std::cout << ch;
}

Supported sequence types:

• STL containers
• arrays
• Null-terminated strings (char and wchar_t)
• std::pair of iterators

For more details see: http://www.boost.org/doc/libs/1_43_0/doc/html/foreach.html

foreach_reverse

#define foreach_reverse   BOOST_REVERSE_FOREACH

This macro provides a more convenient name for BOOST_REVERSE_FOREACH.

The macro can be used similar to foreach, but the containers are traversed in reverse order.

For more details see: http://www.boost.org/doc/libs/1_43_0/doc/html/foreach.html

foreachIt

#define foreachIt	(		var,
			container
	)		for(auto var=container.begin();var!=container.end();++var)

This macro provides a more convenient way for iterating over containers or other sequences that provide iterator concepts.

In contrast to the foreach macros above, this macro provides an iterator instead of the iterated value.

Examples:

std::list<int> list_int;
...
foreachIt(it, list_int )
{
     int val = *it;
}

In fact, this macro is a simple replacement for

for(auto var=container.begin();var!=container.end();++var)