arithmetic operators overloading for class with pointer

[mehjwu]

I am stucked in a problem of overloading arithmetic operators such as "+,*" for a class in the form

class Point
{
    int     N;   //  dimension of the point
    double *Pos; //  length of N
}

My assign operator is :

Point& Point::operator= (const Point& pt)
{
    N= pt.N;
    if(Pos == NULL) Pos = new double[N];
    memcpy(Pos, pt.Pos, N*sizeof(double));
    return *this;
}

operator for multiplication by a double constant "*" is:

Point operator*( double alpha, const Point& pt )
{
    Point ptr = Point(pt);  // this is a constructor
    for (int i=0; i<pt.N;i++)  ptr.Pos[i] *= alpha;
    return ptr;
}

the add operator "+" is:

Point operator+( const Point& pt1, const Point& pt2 )
{
    Point ptr = Point(pt); // this is a constructor
    for (int i=0; i<pt1.N; i++)  ptr.Pos[i] += pt2.Pos[i];
    return ptr;
}

Based on the above overloading, What I am going to do is :

P = alpha*P1 + beta*P2;  // alpha and beta are double constants, P1 and P2 are Points objes 

It is ok with Intel C++ 14.0 compiler, but does not work with the microsoft visual c++ 2012 compiler in debug mode in visual studio 2012.

I stepped in those operators and found that visual c++ compiler deconstructs the ptr in operators "*" and "+" before its return while intel c++ finished the operation P = alpha*P1 + beta*P2; and delete those ptrs at last.

Portability of my operator overloading is worse. I appreciate if anyone can help me with those arithmetic operators overloading for class with pointers in it.
Thanks in advance!

[coder777]

Can you post the code to reproduce the problem?

but does not work with the microsoft visual c++ 2012 compiler

The'd make the compiler unusable

I stepped in those operators and found that visual c++ compiler deconstructs the ptr in operators "*" and "+" before its return while intel c++ finished the operation P = alpha*P1 + beta*P2; and delete those ptrs at last.

That's not a problem. The variable is destructed after the value is copied to another [temporary] variable.

[ne555]

> Point ptr = Point(pt); // this is a constructor
perhaps you should have showed your copy constructor then.
Also, if you are going to copy the arguments, then you could simply ask for a copy instead of a reference.

your 'operator=' is ill-formed for self-assignment

[dhayden]

Your code assumes that N is the same for both points.