C++ Tutorials - Absolute n00b spoonfeed

error C2065: 'energy' : undeclared identifier
error C2065: 'money' : undeclared identifier
These errors are for the constructor. Obviously, I can't assign variables to private member unless I want them to be constant, right? So what to do?

Code: Select all

class Loser
{
public:

   Loser(int startEnergy, int startMoney):
      energy(startEnergy),
      money(startMoney)
      {
     
      };

private:
   int energy;
   int money;
};

int main()
{
   Loser Thang(90, 75);
   Thang.drinkCafe(5,5);
   return 0;
}

   void drinkCafe(int negEnergy, int negMoney)
   {
   energy -= negEnergy;
   money -= negMoney;
   }

could somenoe answeR!!???

jeezcak3 wrote:error C2065: 'energy' : undeclared identifier
error C2065: 'money' : undeclared identifier

That's because drinkCafe is not within the scope of class Loser. You either need to inline the function in the class or create a prototype (forward declaration) in the class and append the class name and :: before drinkCafe when defining it.

jeezcak3 wrote:These errors are for the constructor.

No, function drinkCafe does not know of energy and money because drinkCafe is not in the scope of Loser.

jeezcak3 wrote:Obviously, I can't assign variables to private member unless I want them to be constant, right? So what to do?

Your constructor is fine. You can't assign to private members directly even if they were constant. Constant members need to be initialized through the constructor's initialization list, just like you're doing right now.

my bad. i accidently removed class method drinkcafe there.

even so, it still doesn't know my money and energy

Code: Select all

#include "stdafx.h"
#include <iostream>

using namespace std;

class Loser
{
public:

   Loser(int startEnergy, int startMoney):
      energy(startEnergy),
      money(startMoney)
      {

      };

   void drinkCafe(int negEnergy, int negMoney);

private:
   int energy;
   int money;
};

int main()
{
   Loser Thang(90, 75);
   Thang.drinkCafe(5,5);
   return 0;
}

   void drinkCafe(int negEnergy, int negMoney)
   {
   cout << energy;
   cout << money;
   }


jeezcak3 wrote:even so, it still doesn't know my money and energy

That's correct. You made a prototype for the drinkCafe method in your class but you never define it.
All you did is define a function called drinkCafe.
You need to let the compiler know that you're defining the prototype in class Loser.

Code: Select all

   void Loser::drinkCafe(int negEnergy, int negMoney)
   {
   cout << energy;
   cout << money;
   }


thanks! i figured out.