Refrences and a dog named skinbag.

**CoderMatt** · 02-24-2003

Hey...I need help.

I was atempting to pass a reference through a class method and then use the method to access the private integer 'age' with the reference. This isn't for a program but I need to understand this. Any help would be apreciated.

My compiler is :MSVC++ 6...the error is located at the bottom. What I need to know is how to access the private int age using a reference...thanks.

#include <iostream.h>
class dog //Telling compiler what a dog is..
{
public:
int getAge;
void setAge(int &rAge) //passing a reference
{
rAge=age; //declaring the reference to age.
}

private:
int age;
};

int main()
{
dog SkinBag; //Making my dog...
SkinBag.setAge(5); //error line ... Setting skinbags age

return 0;
}

error:
D:\Vc98\playingaround.cpp(19) : error C2664: 'setAge' : cannot convert parameter 1 from 'const int' to 'int &'
A reference that is not to 'const' cannot be bound to a non-lvalue

**Stoned_Coder** · 02-24-2003

Your code has a few mistakes... heres how it should look....

Code:

class dog
{
   public:
       dog() : Age(0) {}
       dog(int age) : Age(age) {}
       int GetAge() const { return Age;}
       void SetAge(const int age) { Age = age;}
   private:
       int Age;
}

#include <iostream>
using std::cout;
using std::endl;

int main()
{
   dog Fred;
   dog Joe(10);
   cout << Joe.GetAge()<<endl;
   Fred.SetAge(15);
   cout << Fred.GetAge()<<endl;
   Joe = Fred; // uses compiler provided default copy assignment operator.
   cout << Joe.GetAge()<<endl;
   return 0;
}

**CoderMatt** · 02-24-2003

Thank you for responding and helping so quick. As I said though the code is not for a program but for a better understanding of incorperating references with oop class structure and such. Thank you for taking the time to right the code too, unfortunitly the problem still stands, I want to somehow incorperate references into the program.

**Stoned_Coder** · 02-24-2003

The short answer is you dont. For passing an int a reference is less efficient than passing by value. But if you must use a reference change this...

void SetAge(const int age) { Age = age;}

to

void SetAge(const int& age) { Age = age;}

and this

int GetAge() const { return Age;}

to

const int& GetAge() const { return Age;}

**CoderMatt** · 02-24-2003

Thank you thats all I asked for.

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Refrences and a dog named skinbag.

thanks..but...

thanks