C ++中的继承（父类和子类）

Question

I have a parent class called Athlete and there is a child class called TennisPlayer. There are two attributes in my parent class which are name and annual salary. There is also a read method which take in user input for both classes. Here is how my parent looks like:

class Athlete
{
public:
    Athlete();
    Athlete(string name, float annual_salary);
    virtual void read();
    virtual void display();
    string get_name() const;
    float get_annual_salary();
    void set_name(string name);
    void set_annual_salary(float annual_salary);
private:
    string name;
    float annual_salary;
};

class TennisPlayer : public Athlete
{
public:
    TennisPlayer();
    TennisPlayer(string name, float annual_salary, int current_world_ranking);
    int get_current_world_ranking();
    void set_current_world_ranking(int current_world_ranking);
    virtual void read();
    virtual void display();
private:
    int current_world_ranking;
};

The read() method for athlete class works perfectly. But when it comes to tennisPlayer which is the child class, something went wrong, it won't take in the user input, instead it straight away ask me for the input of current world ranking. Here is my .cpp for TennisPlayer class:

void TennisPlayer::read()
{
    cout << "Enter name for tennis player: " ;
    getline(cin, get_name());
    cout << "Enter annual salary for tennis player: ";
        cin >> get_annual_salary();
    cout << "Enter current world ranking: ";
    cin >> current_world_ranking;
}

Conctructor for tennisPlayer class:

TennisPlayer::TennisPlayer(string name, float annual_salary ,int current_world_ranking)
: Athlete(name , annual_salary)
{
    this->current_world_ranking = current_world_ranking;
}

Also there's a problem when reading the annual salary for tennisPlayer. I am not quite familiar with inheritance in C++. Thanks in advance.

Answer 1

At a guess I would say inheritance is not your problem, but getline . Often the 'enter' character is left in the input buffer which means that the next input line seems to be skipped because it just reads this character. Try putting cin.get(); before your call to getline() to flush out this extra character.

EDIT: let me refactor some of your code:

void TennisPlayer::read()
{
    string tennisName;
    float annualSalary;

    cout << "Enter name for tennis player: " ;
    cin.get();  <--read any leftover characters in the input buffer
    getline(cin, tennisName);  <--read in the value
    set_name(tennisName);   <--use parent's mutator to set the value

    cout << "Enter annual salary for tennis player: ";
    cin >> annualSalary;
    set_annual_salary(annualSalary);

}

ADDITIONAL: The child has access to public and protected aspects of the parent class. So an alternative way to do this would be to make the member variables protected so the child class(es) can access them, but they are still hidden from external classes.

Child classes can call public member variables and functions from the parent class without scope resolution ie no need to specify TennisPlayer::set_name , just set_name will suffice.

Answer 2

Try this

void TennisPlayer::read()
{
    cout << "Enter name for tennis player: " ;
    string sName;
    getline(cin, sName);
    set_name( sName );

    cout << "Enter annual salary for tennis player: ";
    float salary;
    cin >> salary;
    set_annual_salary(salary);

    cout << "Enter current world ranking: ";
    int ranking;
    cin >> ranking;
    set_current_world_ranking(ranking);
}

The getter function simply return a value. Changing this value will not do anything to the object from which the value came. You need to call the setter functions in order to actually change the TennisPlayer object.