effective c++ prefer const,enum, inline to #defines

学习心得

对于纯常量，最好以const对象或者enums替换#define

#define FIRST 3 //not good

enum
{
  first=1,
  second=2
} ;

int num[first];

对于macros，最好用inline代替

#define CALL_MAX(a, b) f( (a)>(b) ? (a) : (b))

CALL_MAX(a++,b++); // not right results