Thread: I found an interesting fact about class's initilization list

It's a good habit to initialize all members in a constructor's initialization list.
Sometimes you have multiple constructors in a class, and you have many many members to initialize, you may not want to list them all for each constructor, because if you want to change one member's initialized value, you have to go through all constructors' lists.

Then I found you can use preprocessor:

Code:

#define INI x(0),y(0)

class B{                                                                        
private:                                                                        
    int x,y;                                                                    
public:                                                                         
    B():INI{}                                                                   
    B(int z):INI{}                                                              
    ~B(){}                                                                      
    void print(){cout<<x<<"\t"<<y<<endl;}                                       
};

Very convenient! Just want to share this with you

Originally Posted by meili100

It's a good habit to initialize all members in a constructor's initialization list.
Sometimes you have multiple constructors in a class, and you have many many members to initialize, you may not want to list them all for each constructor, because if you want to change one member's initialized value, you have to go through all constructors' lists.

If you have overloaded constructors, they should be sufficiently different from each other than they don't all require the same initialization list. If you find yourself doing this, see if you can try to apply some default arguments first to cut down on the number of constructors. Classes with more than one constructor tend to be confusing to use. Of course, having a default constructor is always nice, if it makes sense.

Some people recommend placing the common initialization in a private init() method, but this defeats the advantages of the initialization list.