Classes and Inheritance Problems

[D0CHollywood]

I cannot understand why I am getting an error for 'nameInput' and 'weightInput' on Line 15 in Pitcher.cpp. I am simply trying to create a "PITCHER" class derived from the "PLAYER" class.

I have been over this problem for hours, comparing it to similar code, and simply do not get it. I have not even got to writing the main function yet or filled in some of the functions because this problem is holding me up. Any help would be much appreciated.

//          PLAYER.CPP FILE
// Implementation File for Player Class
#include "Player.h"
#include <iostream>

Player::Player() // Default Constructor
{
   name = "Blank";
   weight = 0;
}

Player::Player(string nameInput, int weightInput)
{
   name = nameInput;
   weight = weightInput;
}

void Player::show()
{
   cout << "Name: " << name << endl;
   cout << "Weight: " << weight << endl;
}
  

//         PLAYER.H FILE
// Specification File for Player Class

#ifndef PLAYER_H
#define PLAYER_H
#include<string> // string class included for name of Player
using namespace std; // needed for string 

class Player
{
private:
   string name;
   int weight;

public:
   Player(); //Default Constructor
   Player(string, int); //Constructor to set name and weight

   //Function prototypes
   void show(); //Show method to print name and weight
   
};

#endif 

//           PITCHER.CPP FILE
#include "Pitcher.h"
#include "Player.h"
#include <iostream>  
#include <string>

//PITCHER CLASS DEFINITIONS:

Pitcher::Pitcher()  // Default Constructor
{
   earnedRuns = 0;
   inningsPitched = 0;
}

// ERROR IS ON THE FOLLOWING LINE. nameInput and weightInput below:
Pitcher::Pitcher(int runs, int innings) : Player(nameInput, weightInput)
{
   earnedRuns = runs;
   inningsPitched = innings;
}


float Pitcher::eraCalc(int earnedRuns, int inningsPitched)
{
   float temp;
   temp = ((earnedRuns*inningsPitched) * 9);
   return temp;
}

void Pitcher::show()
{
   cout << "Earned Runs: " << earnedRuns << endl;
   cout << "Innings Pitched: " << inningsPitched << endl;
}

//          PITCHER.H FILE
#ifndef PITCHER_H
#define PITCHER_H
#include "Player.h"

class Pitcher : public Player
{
protected:
   int earnedRuns;
   int inningsPitched;
public:
   Pitcher();  // Default Constructor
   Pitcher(int runs, int innings); // Constructor #2 

   //Function prototypes
   float eraCalc(int, int); // Earned run average calc function
   void show(); //Show method to print earnedRuns, inningsPitched, and calculated ERA
   
};

#endif 

[Peter87]

There are no variables named nameInput or weightInput in scope on line 15 in Pitcher.cpp.

[D0CHollywood]

The Player.cpp references those named variables, which are both in public as part of the constructor. Shouldn't that work?

[E0p9LyTq]

You still need to provide valid values for the Player data members in your Pitcher constructor since you reference the non-default Player constructor.

Your non-default constructor prototype might be
Pitcher(string nameInput, int weightInput, int runsInput, int inningsInput);

[D0CHollywood]

Thanks FurryGuy. If I change the prototype, then the actual definition in the cpp file looks like it needs to change as well, which is confusing, because the order of the prototype is:

Pitcher(int, int, string, int); // Constructor #2  

and the first line of the definition is:

Pitcher::Pitcher(int runs, int innings) : Player(nameInput, weightInput)

But that doesnt seem to work.

[E0p9LyTq]

You need to change the constructor definition as well.

Pitcher::Pitcher(string nameInput, int weightInput, int runsInput, int inningsInput) : Player(nameInput, weightInput)

Remember, function parameters have to match in the declarations and definitions. A constructor is simply a special function.

[D0CHollywood]

That worked! I believe that I was thinking that the function parameter DID already match, because the 4 used variables were listed already, albeit split between the Pitcher and the Player.

Which makes me wonder: If the Pitcher already has all 4 of the used variables, what is the significance/point of the " : Player(nameInput, weightInput)" at the end?

[E0p9LyTq]

Which makes me wonder: If the Pitcher already has all 4 of the used variables, what is the significance/point of the " : Player(nameInput, weightInput)" at the end?

Because Pitcher is a derived class from Player, that bit of code constructs a Player object when it constructs the Pitcher object.

[D0CHollywood]

Ah, gotcha. I really appreciate your help. After hours of struggling, I can finally continue. Thanks!

[E0p9LyTq]

Class inheritance can be somewhat difficult to grasp at first. A quick example might help:

#include <iostream>

class Base
{
public:
   Base()
   {
      itsBaseData = 0;
      std::cout << "Base() constructed!\n";
   }
   Base(int data) : itsBaseData(data)
   {
      std::cout << "Base(int) constructed!\n";
   }
   ~Base()
   {
      std::cout << "Base destructed!\n";
   }

private:
   int itsBaseData;
};

class Derived : public Base
{
public:
   Derived() : Base()
   {
      std::cout << "Derived() constructed!\n";
   }
   Derived(double moreData) : Base()
   {
      itsDerivedData = moreData;
      std::cout << "Derived(int) constructed!\n";
   }
   Derived(int data, double moreData) : Base(data), itsDerivedData(moreData)
   {
      std::cout << "Derived(int, double) constructed!\n";
   }
   ~Derived()
   {
      std::cout << "Derived destroyed!\n";
   }

private:
   double itsDerivedData;
};


int main()
{
   Base* b1 = new Base();
   delete b1;
   b1 = nullptr;
   std::cout << "\n";

   Base* b2 = new Base(150);
   delete b2;
   b2 = nullptr;
   std::cout << "\n";

   Derived* d1 = new Derived();
   delete d1;
   d1 = nullptr;
   std::cout << "\n";

   Derived* d2 = new Derived(8.3);
   delete d2;
   d2 = nullptr;
   std::cout << "\n";

   Derived* d3 = new Derived(150, 8.3);
   delete d3;
   d3 = nullptr;

   return 0;
}

[D0CHollywood]

Awesome, thanks again!