008
21.07.2006, 15:34 Uhr
(un)wissender
Niveauwart
|
So geht es in C++  .
| C++: |
#include <algorithm>
#include <iostream>
#include <iterator>
bool is_prime(unsigned x)
{
if(x < 2) return false;
if(x < 4) return true;
if(x % 2 == 0 || x % 3 == 0) return false;
for(unsigned i = 5, j = 4; i * i <= x; i += (j = 6 - j))
{
if(x % i == 0) return false;
}
return true;
}
class digitIterator
{
public:
explicit digitIterator(unsigned i)
: _current(i)
{
}
digitIterator operator++(int)
{
digitIterator t(_current++);
return t;
}
digitIterator& operator++()
{
++_current;
return *this;
}
bool operator==(digitIterator const & other) const
{
return _current == other._current;
}
bool operator!=(digitIterator const & other) const
{
return !(*this == other);
}
unsigned operator*() const
{
return _current;
}
private:
unsigned _current;
};
template<class InputIterator, class OutputIterator, class Pred>
OutputIterator copy_if(
InputIterator first,
InputIterator last,
OutputIterator destBeg,
Pred pred
)
{
while(first != last)
{
if(pred(*first))
{
*destBeg = *first;
++destBeg;
}
++first;
}
}
int main()
{
copy_if(
digitIterator(0),
digitIterator(101),
std::ostream_iterator<unsigned>(std::cout, " "),
&is_prime);
}
|
--
Wer früher stirbt ist länger tot. |
