alg51.c

“在遇到无法解决的问题时

#include <algorithm>
#include <vector>
#include <iterator>
#include <iostream.h>

class print_elements {
public:
        void operator()( string elem ) {
                 cout << elem
                      << ( _line_cnt++%8 ? " " : "\n\t" );
        }
        static void reset_line_cnt() { _line_cnt = 1; }

private:
        static int _line_cnt;
};

int print_elements::_line_cnt = 1;

/* generates:
original list of strings:
        The light untonsured hair grained and hued like
        pale oak 

sequence after copy_backward( begin+1, end-3, end ):
The light untonsured hair light untonsured hair grained
        and hued 
*/

int main()
{
        string sa[] = { "The", "light", "untonsured", "hair",
			"grained", "and", "hued", "like", "pale", "oak" };

        vector< string, allocator > svec( sa, sa+10 );

        cout << "original list of strings:\n\t";
        for_each( svec.begin(), svec.end(), print_elements() ); cout << "\n\n";

	copy_backward( svec.begin()+1, svec.end()-3, svec.end() );

        print_elements::reset_line_cnt();

        cout << "sequence after copy_backward( begin+1, end-3, end ):\n";
        for_each( svec.begin(), svec.end(), print_elements() );
        cout << "\n";
}