Thread: The use of const and &

Let's say i create a class:

Code:

class myClass { ... };

I'm used to passing it like this for read-only functions:

Code:

const myClass& aName

But i realised that some problems come up, so i figured this:

Code:

const myClass& aName // for using its member variables
const myClass aName // for using it directly

Could you tell me if there is a benefit of using this method, if it is correct?

Originally Posted by Sipher

Could you tell me if there is a benefit of using this method, if it is correct?

Use the reference whenever you pass a class to a function. It prevents the class from being copied when it's passed to a function.

Code:

class aClass
{
   public:
       int a;
       
       const aClass Sum(const aClass& c)
       {
          aClass Result;
    
          Result.a = a + c.a;

          return Result;
       }
 
       void SumTo(const aClass c)
       {
          *this = Sum(c);
       }
   
};

By saying 'using its member variables' i mean using the Sum member functions
By saying 'using it directly' i mean using the SumTo

This is of course a very rough example, but that's the idea.

The compiler, when i pass an aClass through another struct or class instance, throws an error that 'this' function discards qualifiers. What does it mean?

Many thanks for the interest guys!