Overloaded Operators
Operator overloading has changed significantly from Managed Extensions for C++ to Visual C++ 2008.
In the declaration of a reference type, for example, rather than using the native operator+ syntax, you explicitly write out the underlying internal name of the operator – in this case, op_Addition. In addition, the invocation of an operator has to be explicitly invoked through that name, thus precluding the two primary benefits of operator overloading: (a) the intuitive syntax, and (b) the ability to intermix new types with existing types. For example:
public __gc __sealed class Vector {
public:
Vector( double x, double y, double z );
static bool op_Equality( const Vector*, const Vector* );
static Vector* op_Division( const Vector*, double );
static Vector* op_Addition( const Vector*, const Vector* );
static Vector* op_Subtraction( const Vector*, const Vector* );
};
int main()
{
Vector *pa = new Vector( 0.231, 2.4745, 0.023 );
Vector *pb = new Vector( 1.475, 4.8916, -1.23 );
Vector *pc1 = Vector::op_Addition( pa, pb );
Vector *pc2 = Vector::op_Subtraction( pa, pc1 );
Vector *pc3 = Vector::op_Division( pc1, pc2->x );
if ( Vector::op_Equality( pc1, pc2 ))
;
}
In the new syntax, the usual expectations of a native C++ programmer are restored, both in the declaration and use of the static operators. Here is the Vector class translated into the new syntax:
public ref class Vector sealed {
public:
Vector( double x, double y, double z );
static bool operator ==( const Vector^, const Vector^ );
static Vector^ operator /( const Vector^, double );
static Vector^ operator +( const Vector^, const Vector^ );
static Vector^ operator -( const Vector^, const Vector^ );
};
int main()
{
Vector^ pa = gcnew Vector( 0.231, 2.4745, 0.023 );
Vector^ pb = gcnew Vector( 1.475,4.8916,-1.23 );
Vector^ pc1 = pa + pb;
Vector^ pc2 = pa - pc1;
Vector^ pc3 = pc1 / pc2->x;
if ( pc1 == pc2 )
;
}