Create a default constructor when using const strings

Question

I have a class that looks like this:

Person(int pID,
    int zipCode,
    float ySalary,
    const string& fName,
    const string& mName,
    const string& lName)

When I try to create a default constructor as shown below:

Person::Person(void){
    zipCode = NULL;
    pID = NULL;
    ySalary = NULL;
    fName = "";
    mName = "";
    lName = "";
}

I get an error saying there is no operator "=" that matches const std::string = const char[1];

Answer 1

You need to use the member initializer list to initialize const reference member variables:

Person::Person(void) :
    zipCode(NULL) ,
    pID(NULL) ,
    ySalary(NULL) ,
    fName("") ,
    mName("") ,
    lName("") { 
}

I'd recommend always to use the member initializer list syntax, preferred to assignments in the constructor body. See here for example: What is the advantage of using initializers for a constructor in C++?