对象顺序表C;Field by choice

Question

经过大量的研究和尝试来解决这个问题

我想知道是否有一种在c++中排序对象列表的方法;

到目前为止我看到的所有解决方案，我们必须事先定义哪个阵营将用于排序。

我想要的是用户可以自由选择使用哪个阵营进行排序这是我的代码

class LOL
{
   public:
   LOL( const string& Nickname = "", int skill = 0,int level= 0 );
   bool operator > ( const LOL &rhs ) const; 
   void print() const;
   private:
   int level_;
   string Nickname_;
   int skill_;
};
inline
LOL::LOL( const string& Nickname, int skill, int level)
   : level_( level), Nickname_( Nickname ), skill_( skill )
{} 

inline
bool LOL::operator > ( const LOL& rhs ) const
{ return Nickname_  > rhs.Nickname_; } 

inline
void LOL::print() const
{ cout << Nickname_ << " from level " << level_
   << " has skill of [ " << skill_ <<" ]"<< endl<< endl;
}
int main( )
{
   list<LOL> list1;
   list1.push_back( LOL( "Dhespair", 50000, 30 ) );
   list1.push_back( LOL( "Pedro", 1, 1 ) );
   list1.push_back( LOL( "Blackblood", 99999, 30 ) );
   list1.push_back( LOL( "Zladovic", 30000, 25 ) );
   list1.sort( greater <LOL>()  );
   for_each( list1.begin(), list1.end(), mem_fun_ref( &LOL::print ) );
   printf("nn");
   system("pause");
}

经过几次尝试，我想出了这个解决方案

class LOL
{
   public:
   LOL( const string& Nickname = "", int skill = 0,int level= 0 , int op=1);
   bool operator > ( const LOL &rhs        ) const; // MUDAR O > para maior  ou < MENOR
   bool operator < ( const LOL &rhs        ) const; // MUDAR O > para maior  ou < MENOR
   void print() const;
   private:
   int level_;
   string Nickname_;
   int skill_;
   int op_;
};
inline
LOL::LOL( const string& Nickname, int skill, int level, int op)
   : level_( level), Nickname_( Nickname ), skill_( skill ), op_( op )
{} 

inline
bool LOL::operator > ( const LOL& rhs ) const
{ 
    switch(rhs.op_)
    {
    case 1:
    return Nickname_  > rhs.Nickname_; 
    break;
    case 2:
    return level_  > rhs.level_; 
    break;
    case 3:
    return skill_ > rhs.skill_; 
    break;
    } // MUDAR O  > para maior  ou < MENOR e ESCOLHER CAMPO A TER EM CONTA
}
inline
bool LOL::operator < ( const LOL& rhs ) const
{ 
    switch(rhs.op_)
    {
    case 1:
    return Nickname_  < rhs.Nickname_; 
    break;
    case 2:
    return level_  < rhs.level_; 
    break;
    case 3:
    return skill_ < rhs.skill_; 
    break;
    } // MUDAR O  > para maior  ou < MENOR e ESCOLHER CAMPO A TER EM CONTA
}

inline
void LOL::print() const
{ cout << Nickname_ << " from level " << level_
   << " has skill of [ " << skill_ <<" ]"<< endl<< endl;
}
int main( )
{
   list<LOL> list1;
   list1.push_back( LOL( "Dhespair", 50000, 30,3 ) );
   list1.push_back( LOL( "Pedro", 1, 1,3 ) );
   list1.push_back( LOL( "Blackblood", 99999, 30,3) );
   list1.push_back( LOL( "Zladovic", 30000, 25,3 ) );
   list1.sort( less <LOL>()  );
   for_each( list1.begin(), list1.end(), mem_fun_ref( &LOL::print ) );
   printf("nn");
   system("pause");
}

我所做的是给对象添加一个新值，我将使用该值在bool操作符内操作switch case。

它可以工作，但是如果有人知道一种不用在我的对象中添加新参数就可以使用该开关的方法，我将非常感谢x)

Answer 1

bool compareTwoLOLObjectsWay1(LOL &A, LOL &B)
{
  /* Logic to determine if A<B */
}
bool compareTwoLOLObjectsWay2(LOL &A, LOL &B)
{
  /* Logic to determine if A>B */
}
switch(sortWay)
{
  case 1:
    list1.sort(&compareTwoLOLObjectsWay1);
    break;
  case 2:
    list1.sort(&compareTwoLOLObjectsWay2);
    break;
}