silly question on Operator Overloading
Author
i been stuck on Operator Overloading mainly because i really dont understand its concept :*)
can someone explain to me what exactly the difference in overloading an operator?
for example the +
it be easier to learn it if i knew and understood but,after reading almost a half chapter of it,i am still clueless as to what exactly its doing :*)
told you it was a silly question,somebody help me please :(
So what exactly are you confused about?
The + operator is a simple example to work with. C++ defines the + operator for all built-in types for which it makes sense; you can add ints, floats, doubles, etc., as you would expect.
The classic example of operator overloading is for a vector class. Let's say you have a 3d vector class, like this:
class Vector
{
public: float x, y, z;
};
You may already know that you add vectors by adding their components. Without operator overloading, every time you wanted to add two vectors, you would have to write:
v.x = v1.x+v2.x;
v.y = v1.y+v2.y;
v.z = v1.z+v2.z;
Hard to type, hard to read, and introduces the possibility of error. It would be much better if you could just write:
v = v1+v2;
And by overloading the + operator for class Vector, you can.
Once you understand the concept, it's just a matter of learning the syntax, which your book should be able to help you with.
[Edit: Actually there are ways to avoid writing it out every time without using operator overloading, but if you're using C++ you might as well use the tools it provides, as they have some advantages over the other methods.]
The + operator is a simple example to work with. C++ defines the + operator for all built-in types for which it makes sense; you can add ints, floats, doubles, etc., as you would expect.
The classic example of operator overloading is for a vector class. Let's say you have a 3d vector class, like this:
class Vector
{
public: float x, y, z;
};
You may already know that you add vectors by adding their components. Without operator overloading, every time you wanted to add two vectors, you would have to write:
v.x = v1.x+v2.x;
v.y = v1.y+v2.y;
v.z = v1.z+v2.z;
Hard to type, hard to read, and introduces the possibility of error. It would be much better if you could just write:
v = v1+v2;
And by overloading the + operator for class Vector, you can.
Once you understand the concept, it's just a matter of learning the syntax, which your book should be able to help you with.
[Edit: Actually there are ways to avoid writing it out every time without using operator overloading, but if you're using C++ you might as well use the tools it provides, as they have some advantages over the other methods.]
In short, overloading an operator allows you to use those operators on your own data types. Say for instance, you have a class Grid:
And you have a Grid now:
Overloading the ++ operator can allow you to do a number of things.
So now you can do this:
And now the values which were 3,2 are now 4,3.
If you still don't understand, feel free to come back and ask.
class Grid{public: int x; int y; Grid operator++();};And you have a Grid now:
Grid myGrid;myGrid.x = 3;myGrid.y = 2;Overloading the ++ operator can allow you to do a number of things.
Grid Grid::operator++(){ x++; y++; Grid temp; temp.x = this->x; temp.y = this->y; return Grid;}So now you can do this:
Grid = Grid++;And now the values which were 3,2 are now 4,3.
If you still don't understand, feel free to come back and ask.
Author
yeah,i am still confused about it :(
maybe i should go back and review Classes and Pointers,i sort of understand it but i still fail to see where the operator ++ changes or what its doing :(
but thanks you two for trying,it should be easy but i just cant figure it out
....
so this whole thing:
Grid Grid::operator++()
{
x++;
y++;
Grid temp;
temp.x = this->x;
temp.y = this->y;
return Grid;
}
is only to make it easier by typing this:
Grid = Grid++;
is this what Operator overloading means? :*)
maybe i should go back and review Classes and Pointers,i sort of understand it but i still fail to see where the operator ++ changes or what its doing :(
but thanks you two for trying,it should be easy but i just cant figure it out
....
so this whole thing:
Grid Grid::operator++()
{
x++;
y++;
Grid temp;
temp.x = this->x;
temp.y = this->y;
return Grid;
}
is only to make it easier by typing this:
Grid = Grid++;
is this what Operator overloading means? :*)
Operators in C++ are implemented using functions. For example, the name of the function for the '+' operator is "operator+". When you overload an operator, you are overloading its function. "Overloading a function" means to provide another function with same name but different parameters.
Now, classes don't have most operators automatically created for them, so if you want an operator for a class, you have to write it yourself. A good example of where creating operators is handy is a 3D vector class.
If you want to add two vectors, you could write this function.
Now, classes don't have most operators automatically created for them, so if you want an operator for a class, you have to write it yourself. A good example of where creating operators is handy is a 3D vector class.
If you want to add two vectors, you could write this function.
vector3 Add( vector3 const & a, vector3 const & b ) { vector3 result; result.x = a.x + b.x; result.y = a.y + b.y; result.z = a.z + b.z; return result; } ... vector3 d,e,f; d = Add( e, f ); vector3 operator+( vector3 const & a, vector3 const & b ) { vector3 result; result.x = a.x + b.x; result.y = a.y + b.y; result.z = a.z + b.z; return result; } ... vector3 d,e,f; d = e + f; d = operator+( e, f ); This topic is closed to new replies.
Advertisement
Popular Topics
Advertisement