Discussion on Messages Order Challenge

1 year ago+ 0 comments

I think my approach is quite similar to the others already published here. It involves the usage of a static variable.

I added a static variable "order", class-wise.
In addition, each instance of Message also contains its own copy of order, called order_.
On creation time, Message() calls set_order() which increments the global order by one, then copies that value to the interval variable order_. For that, the Message's constructor calls set_order().
Messages are sorted by order_.

class Message {
public: 
    Message() {
        // this will set the order or arrival, on creation time
        set_order();
    }
    Message(const string text): Message() {text_=text;}
    const string& get_text() {
        return text_;
    }
    
    // global variable to keep count of the number of messages created
    static int order;
    // public getter function
    int get_order() const { return order_; }
    // comparison operator
    bool operator<(const Message& other) const {
        return order_ < other.get_order();
    }
private:
    string text_;
    
    // this is for internal use
    int order_;
    // this is called on creation time: set the order of arrival for the message
    void set_order() { order_ = ++Message::order; }
};
int Message::order = 0;

class MessageFactory {
public:
    MessageFactory() {}
    Message create_message(const string& text) {
        return Message(text);
    }
};

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