Design issue.

[Sausage]

Hey guys,

I have an exercise that wants me to identify the design issue with this code snippet.

I'm a little unsure as to what the design issue is? It functions correctly. I'm guessing it's because the GetHunger prototype is returning m_Hunger in the class? Also the data member m_Hunger hasn't been initialized?

  #include <iostream>

using namespace std;

class Critter 
{
 public:
   int GetHunger() const {return m_Hunger;}
 private:
   int m_Hunger;
};

int main() 
{
  Critter crit;
  cout << crit.GetHunger() << endl;
  return 0;
 }

Thanks for any help.

[Electodemon]

Heed this answer with a grain of salt, for I could be entirely wrong and I pray someone corrects me if I am, but in my attempt to be helpful.

My speculation is that GetHunger() is a public class, but m_Hunger is a private class, which I think means that m_Hunger can not be changed and therefor constant, but I would imagine that the Hunger of said critter would vary over time?

I only say that because under the private class m_Hunger isn't a constant, which why leave it open to change if it isn't meant to be?


-- Again I apologize if I am dead wrong :|

[Sausage]

Thanks for replying!

No I think you're right, the value of m_Hunger will change depending upon certain situations hence why it's not been declared with a default value.

I'm guessing the problem comes down to bad design within the class; I THINK the issue surrounds returning a data member that hasn't been initialized to any value yet? Possibly GetHunger is declared and initialized within the class?

[Little Captain]

Everything is correct in the code. What the problem is is that there is no constructor initializing the member data to a known state. What you'd be printing are garbage values.

The GetMember() function defined as const is a good thing. It means that you cannot alter the data member's value inside that function.

Joe - C++ tutor

[Sausage]

Hey Joe,

So I should write a constructor that initializes m_Hunger like this.

#include <iostream>

using namespace std;

class Critter {
public:
	Critter(int food = 0);
	int GetHunger() const {return m_Hunger;}
private:
	int m_Hunger;
};

Critter::Critter(int food) :
m_Hunger(food)
{}

int main() {
	Critter crit;
	cout << "My hunger level is: " << crit.GetHunger();

}

[Little Captain]

Right. :)