Objects as members of classes

[cher1201]

So I am trying to write a class called undergraduate that takes an object of the Phone class as an argument. However, the phone class uses a const data member called msg. This will not compile because of the const data member in the phone class. How do I fix it? Any help will be greatly appreciated!

//Below is my default constructor for the Phone class, it uses const data member msg

Phone::Phone():msg(10){ //intialize const data member

        areacode = 999;

        exchange = 999;

        line = 9999;
}

//here is my constructor that takes objects as arguments

Undergraduate::Undergraduate(Name sname, Date bday, Program sprogram, Phone sphone, char g, string s, int c, double G, int gdyr, string term){

        name = sname;
        date = bday;
        pgm = sprogram;
        phone = sphone;

        gender = g;
        status = s;
        credit = c;
        gpa = G;
        gradyear = gdyr;
        gradterm = term;
}

 

[Peter87]

To solve this issue you should initialize the member variables in the constructor initialization list, like you do with msg in the Phone constructor.

[cher1201]

Thank you so much for responding. How exactly would I go about doing this?

[Peter87]

You list the member variables, followed by the value they should be initialized with inside parentheses, separated by comma after the ) and before the {.

This is how it would look like for the Phone constructor.

Phone::Phone() : msg(10), areacode(999), exchange(999), line(9999) { }

You only strictly need to do this for the members that you can't assign to later, like Phone::msg and Undergraduate::phone, but it's generally considered the prefered way to initialize member variables so I recommend doing it for all of them.

[cher1201]

thanks!