// This file will create various functors (function object types) for 
// managing various conditions

class Always
{
public:
   bool operator() (int x)	{   return true;   }
};

class IsPos
{
public:
   bool operator() (int x)	{   return (x > 0);   }
};

class IsNeg
{
public:
   bool operator() (int x)	{   return (x < 0);   }
};

class IsEven
{
public:
   bool operator() (int x)	{   return (x % 2 == 0);   }
};

class IsOdd
{
public:
   bool operator() (int x)	{   return (x % 2 != 0);   }
};

class IsDivisBy3
{
public:
   bool operator() (int x)	{   return (x % 3 == 0);   }
};