Re: initializing a vector with a sequence of 0, ..., N-1
In article <1146010066.555718.229090@i40g2000cwc.googlegroups.com>,
ma740988 <ma740988@gmail.com> wrote:
Carlos Moreno wrote:
Where the default ctor for the iterator constructs an
iterator with state equivalent to end-of-range, and the
second parameter for the two-argument ctor indicates
when the iterator should become end-of-range.
At least it should be fun as an exercise :-) (and it does
have the added value that the vector is initialized with the
range in one shot, along with instantiation -- no need to
create it empty and then re-assign values to it).
I found the thread in general interesting since I too am often faced a
similar dilema. How would handle a case like this?
double arr [ 10 ] = { 1., 0., 2., 0., 3., 0., 4., 0., 5., 0. };
can use a transform_iterator of a counting iterator.
struct func:public std::unary_function<double,int>
{
double operator () (int x) {return x % 2;0:1+x/2;}
};
typedef boost::transform_iterator
<
func,
boost::counting_iterator<int>
my_iterator;
inline my_iterator make_my_iterator(int x)
{ return my_iterator(boost::counting_iterator<int>(x),
func());
}
std::vector<double> array
(
make_my_iterator(0),make_my_iterator(10)
);
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