Effetive C + + 02 try to replace # define with Const,enum,inline

#define aspect_ratio=1.1
Const Double aspectratio=1.1

1. Using a macro causes the preprocessor to unconditionally replace the Aspect_ratio in the program code with 1.1, the compiler has never seen Aspect_ratio, debug compilation can be difficult to track, and the const constant resolves the problem.

2. The scope of the macro definition is the subsequent compilation process until it is #undef, so the macro definition cannot be used as an exclusive constant for the class, for example, we want to define an array in the class, the size of the array requires a constant, we will do this in the following way:

class test{private:    staticconstint3;  Static can guarantee that the constants have    only one entity int  array[num];}

In addition to using const to define constant values, we can also use Enum to implement

class test{private:    enum3 };  // enumeration values can be used    when int int array[num];}

3. For the macro function, we can use the inline function instead, some people say that the macro can not limit the parameter type, function is not, this can be achieved through the template function.

#define Max (b)  F ((a) > (b)? (a): (b)template<typename t>void Max (constconst t& b) {      > B? a:b)}

Effetive C + + 02 try to replace # define with Const,enum,inline