algo/perm1.cpp

The following code example is taken from the book
The C++ Standard Library - A Tutorial and Reference
by Nicolai M. Josuttis, Addison-Wesley, 1999
© Copyright Nicolai M. Josuttis 1999


#include "algostuff.hpp"
using namespace std;

int main()
{
    vector<int> coll;

    INSERT_ELEMENTS(coll,1,3);
    PRINT_ELEMENTS(coll,"on entry:  ");

    /* permute elements until they are sorted
     * - runs through all permutations because the elements are sorted now
     */
    while (next_permutation(coll.begin(),coll.end())) {
        PRINT_ELEMENTS(coll," ");
    }
    PRINT_ELEMENTS(coll,"afterward: ");

    /* permute until descending sorted
     * - this is the next permutation after ascending sorting
     * - so the loop ends immediately
     */
    while (prev_permutation(coll.begin(),coll.end())) {
        PRINT_ELEMENTS(coll," ");
    }
    PRINT_ELEMENTS(coll,"now:       ");

    /* permute elements until they are sorted in descending order
     * - runs through all permutations because the elements are sorted
     *    in descending order now
     */
    while (prev_permutation(coll.begin(),coll.end())) {
        PRINT_ELEMENTS(coll," ");
    }
    PRINT_ELEMENTS(coll,"afterward: ");
}