January 3rd, 2008
I have finally found a practical use of mutable keyword in C++ 
Suppose we have a class and we want to do some "lazy loading":
C++:
class Foo
{
private:
Bar *bar;
public:
const Bar& GetBar
() const;
};
const Bar& Foo::GetBar() const
{
// lazy loading
if(bar == NULL)
{
bar = new Bar();
}
}
Everything would be fine but the const keyword does not allow us to change a value of a bar pointer.
That's the place where mutable is useful 
C++:
class Foo
{
private:
mutable Bar *bar;
public:
const Bar& GetBar
() const;
};
const Bar& Foo::GetBar() const
{
// lazy loading
if(bar == NULL)
{
bar = new Bar();
}
}
Happy coding
November 17th, 2007
Few days ago I found very interesting piece of code in polish usenet. The code is correct and it works fine but it looks like... yes, like vomit. C++ programmers, can I have a request? Please, do not move features from other languages that we can live without, to the C++.
C++:
void increment
(int &i
)
{
++i;
}
static void test1()
{
boost::function<void (int &)> add1=::increment;
std::vector<std::vector<int>> vec(10, std::vector<int>(10, 2010));
std::for_each(vec.begin(), vec.end(), boost::lambda::bind(boost::lambda::ll::for_each(),
boost::lambda::bind(boost::mem_fn((std::vector<int>::iterator(std::vector<int>::*)())
&std::vector<int>::begin), boost::lambda::_1),
boost::lambda::bind(boost::mem_fn((std::vector<int>::iterator(std::vector<int>::*)())
&std::vector<int>::end), boost::lambda::_1),
add1));
std::for_each(vec.begin(), vec.end(), boost::lambda::bind(boost::lambda::ll::copy(),
boost::lambda::bind(boost::mem_fn((std::vector<int>::iterator(std::vector<int>::*)())
&std::vector<int>::begin), boost::lambda::_1),
boost::lambda::bind(boost::mem_fn((std::vector<int>::iterator(std::vector<int>::*)())
&std::vector<int>::end), boost::lambda::_1),
std::ostream_iterator<int>(std::cout, " ")));
std::cin.get();
}
