Specifying sorting criteria in C + + at execution time

1 //functor that defines the collation criteria2template<classT>3 classruntimecmp4 {5  Public:6     enumCmp_mode {_normal, _reverse};7  Public:8RUNTIMECMP (Cmp_mode m =_normal): Mode (m) {}9 Ten     BOOL operator() (ConstT &t1,ConstT &t2)Const{returnmode = = _normal? T1 < T2:t2 <T1;} // overload () operator   One     BOOL operator== (Construntimecmp &AMP;RC) {returnmode = =Rc.mode;} A  - Private: - cmp_mode mode; the }; -  - intMain () - { +typedefSet<int, runtimecmp<int> >Intset; - Intset coll1; +Coll1.insert (4); AColl1.insert (7); atColl1.insert (5); -Coll1.insert (1); -Coll1.insert (6); -Coll1.insert (2); -Coll1.insert (5); -cout <<"coll1:"; inCopy (Coll1.begin (), Coll1.end (), ostream_iterator<int> (cout," ")); -cout <<Endl; to  +runtimecmp<int> Reverse_order (runtimecmp<int>:: _reverse); -  the intset coll2 (reverse_order); *Coll2.insert (4); $Coll2.insert (7);Panax NotoginsengColl2.insert (5); -Coll2.insert (1); theColl2.insert (6); +Coll2.insert (2); AColl2.insert (5); the  +cout <<"coll2:"; -Copy (Coll2.begin (), Coll2.end (), ostream_iterator<int> (cout," ")); $cout <<Endl; $  -COLL1 =coll2; -Coll1.insert (3); thecout <<"coll1:"; -Copy (Coll1.begin (), Coll1.end (), ostream_iterator<int> (cout," "));Wuyicout <<Endl; the  -     //test whether the coll1 and coll2 sorting criteria are the same Wu     if(Coll1.value_comp () = =Coll2.value_comp ()) -     { Aboutcout <<"Coll1 and coll2 have same sorting criterion"<<Endl; $     } -     Else -     { -cout <<"Coll1 and coll2 have different sorting criterion"<<Endl; A}

Program output:

Coll1:1 2 4 5 6 7

Coll2:7 6 5 4 2 1

Coll1:7 6 5 4 3 2 1

Coll1 and coll2 have same sorting criterion

Note: The assignment operator also assigns the sorting criteria

See standard C + + library

Specifying sorting criteria in C + + at execution time