关联容器执行器指定排序规则

//
//  main.cpp
//  setcmp
//
//  Created by IDM-PKU on 14-9-6.
//  Copyright (c) 2014年 PKU. All rights reserved.
//

#include <iostream>
#include <set>
#include "print.hpp"

using namespace std;

template <class T>
class RuntimeCmp{
    public:
    enum cmp_mode{normal,reverse};
    private:
    cmp_mode mode;
    public:
    RuntimeCmp(cmp_mode m=normal):mode(m)
    {}
    bool operator()(const T& t1, const T& t2) const
    {
        return (mode==normal) ? (t1<t2) : (t2<t1);
    }
    
    bool operator==(const RuntimeCmp& rc)
    {
        return mode==rc.mode;
    }
    
};

typedef set<int,RuntimeCmp<int>> IntSet;

void fill(IntSet & set);

int main(int argc, const char * argv[])
{
    IntSet coll1;
    fill(coll1);
    PRINT_ELEMENTS(coll1,"coll1: ");
    RuntimeCmp<int> reverse_order(RuntimeCmp<int>::reverse);
    
    IntSet coll2(reverse_order);
    fill(coll2);
    PRINT_ELEMENTS(coll2,"coll2: ");
    
    coll1=coll2;
    coll1.insert(3);
    PRINT_ELEMENTS(coll1,"coll1: ");
    if(coll1.value_comp()==coll2.value_comp())
    {
        cout << "coll1 and coll2 have same sorting criterion" << endl;
    }
    else
    {
        cout << "coll1 and coll2 have different sorting criterion" << endl;
    }
    return 0;
}

void fill(IntSet & set)
{
    set.insert(4);
    set.insert(7);
    set.insert(5);
    set.insert(1);
    set.insert(6);
    set.insert(2);
    set.insert(5);
}